JP2017196632A - Burring processing device, burring processing method and burring molded part - Google Patents

Abstract

A burring device capable of freely forming a corner portion is provided. A burring device for obtaining a molded product having a cylindrical stretch flange portion by burring a workpiece, comprising a flat portion and a projection portion having a shape corresponding to the inner surface shape of the stretch flange portion. and a movable die that is movably provided relative to the fixed die in the projecting direction of the protrusion and supports the flange peripheral portion around the stretch flange portion, and between the movable die In the flange peripheral part, the first punch that sandwiches the outer edge area that is on the outer edge than the flange edge area on the edge of the stretched flange part, and the movable die that is in contact with the flat part of the fixed die On the other hand, it is pushed in later than the first punch, stretches and constrains the flange portion between the side surface of the protrusion, and pinches the flange peripheral region of the flange peripheral portion between the movable die to cut the corner portion. and a second punch for shaping. [Selection drawing] Fig. 3

Description

  The present invention relates to a burring apparatus, a burring method, and a burring molded product.

  Burring is a processing method in which a flange is formed at the edge of a pilot hole provided in a workpiece. In burring, a punch is pushed into the pilot hole in the workpiece, and the peripheral edge of the pilot hole in the workpiece is stretched in the direction in which the punch is pushed, thereby forming an elongated flange that protrudes from the edge of the pilot hole in the workpiece. .

  For example, Patent Document 1 discloses a pre-forming step in which a convex portion is formed in a rising direction of a rising portion at a portion where a plate material is to be subjected to burring processing by pressing, and a convex portion formed in the preliminary forming step by punching processing. A plate material comprising: a punching process in which a hole having a diameter smaller than a diameter of a hole finally obtained is formed in a part; and a main forming process in which a raised part is deeply drawn by pressing to form a rising part. The burring method is disclosed. In such a burring method, by performing the preforming step, the press conforming to the shape of the convex shape and the concave shape is not performed, so the elongation becomes uniform, and even in a material with a small elongation, no crack occurs at the tip of the rising portion, Also, the thickness can be made uniform.

Japanese Patent Laid-Open No. 2004-223583

  The burring portion formed on the workpiece by burring is used, for example, as a screw attachment portion in the hollow portion of the stretch flange portion. In this case, it is necessary to secure the strength that can withstand attachment to the screw. However, in the burring process, the material of the edge region of the pilot hole of the work material is stretched to form the stretch flange part, so the plate thickness of the stretch flange part is smaller than the plate thickness of the work material before burring process. . Therefore, if the thickness increase is performed as it is in order to increase the thickness of the stretch flange portion formed by burring, the inside of the corner portion formed by the stretch flange portion and the flange peripheral portion around the stretch flange portion will be described. The flange peripheral portion and the stretch flange portion overlap each other, and folding is likely to occur. Since the generated folding is removed by cutting, the cutting cost is high. Further, in order to prevent burrs from being generated, a blanking process for removing burrs is required.

  Also in the burring method described in Patent Document 1, the corner portion formed by the plate material and the inner surface of the rising portion corresponding to the stretch flange portion is thinner than the thickness of the plate material before processing. The strength cannot be secured.

  Therefore, the present invention has been made in view of the above problems, and the object of the present invention is to provide a novel and improved capable of realizing free forming of the corner portion. Another object is to provide a burring apparatus, a burring method, and a burring molded product.

  In order to solve the above problems, according to one aspect of the present invention, there is provided a burring apparatus for burring a workpiece to obtain a molded product having a cylindrical stretch flange portion, the plane portion, A fixed die having a protrusion protruding from the flat surface and having a shape corresponding to the shape of the inner surface of the extending flange portion, and provided around the fixed flange so as to be movable in the protruding direction of the protruding portion. The outer peripheral region located on the outer side of the flange peripheral portion is sandwiched between the movable die and the movable die that supports the movable portion, and the peripheral portion of the flange. The movable die that is in contact with the first punch and the movable die that is in contact with the flat portion of the fixed die is pushed behind the first punch and extends between the side surface of the protruding portion to restrain the flange portion, and the movable die Between and flange Comprising a second punch for forming a corner portion formed by the flange edge region and stretch flange sandwiches the flange edge regions of the surrounding portion, the punch comprising, a burring apparatus is provided.

  The workpiece has a flat plate shape having a pilot hole at the start of burring, and the first punch and the second punch have a flat plate shape with the second punch retracted from the first punch. You may shape | mold the outer edge area | region of a stretch flange part and a flange peripheral part by pushing a workpiece into the plane part of a fixed die.

  You may shape | mold a corner part so that plate | board thickness may become larger than a stretch flange part and a workpiece.

  The punch may further include a third punch that is brought into contact with the end face of the extending flange portion on the opposite side of the corner portion and is pushed toward the flat portion of the fixed die after the corner portion is formed by the second punch. Good.

  The outside of the corner portion may be formed at a substantially right angle.

  In order to solve the above-mentioned problem, according to another aspect of the present invention, there is provided a burring method for burring a workpiece to obtain a molded product having a cylindrical elongated flange portion. The portion corresponding to the flange portion is made to correspond to the protruding portion protruding from the flat portion of the fixed die, and the flange peripheral portion around the extending flange portion is made to correspond to the movable die movable in the protruding direction of the protruding portion with respect to the fixed die. As described above, the step of placing the workpiece on the die, and the outer part located on the outer side of the flange edge region on the edge of the extended flange part of the flange peripheral part between the first punch and the movable die A step of pushing the first punch and the second punch that constrains the flange portion between the side surfaces of the projecting portion while holding the side region until the movable die contacts the flat portion of the fixed die; and Contact the flat part of the fixed die The second punch is pushed into the movable die with a delay from the first punch in a state where the outer region is sandwiched between the movable die and the first punch, and is formed by the flange peripheral region and the extending flange portion. Forming a corner portion to be processed.

  The burring method further includes a step of, after forming the corner portion by the second punch, pushing the third punch abutted against the end face of the extending flange portion opposite to the corner portion toward the flat portion of the fixed die. May be included.

  Further, a molded product having a cylindrical stretch flange portion obtained by burring is used as the second workpiece, and the shape corresponds to the shape of the second molded product, and the hollow portion of the stretch flange portion is inserted. And a second die having a second flat portion supporting the flange peripheral portion around the stretch flange, and sandwiching the flange peripheral portion together with the second flat portion of the second die And a fourth punch for pressing the end face of the elongated flange portion, and a fifth punch for forming the second molded product, the flange peripheral portion is made to be the second flat portion and the fourth punch portion. You may further include the process of shape | molding a 2nd molded article by pushing in the end surface of an extending flange part with a 5th punch in the state clamped with the punch.

  Here, the second protrusion of the press molding apparatus is formed with a diameter smaller than the inner diameter of the elongated flange portion, and the fifth peripheral portion is sandwiched between the second flat portion and the fourth punch, The end face of the stretch flange portion may be pushed in by using the punch to increase the thickness of the stretch flange portion.

  Of the second die of the press molding apparatus, the second flat surface portion that supports the flange peripheral portion is a fixed die that supports a region other than the corner portion of the flange peripheral portion, the corner portion is supported, and the extension flange The movable die is moved by pushing the end face of the elongated flange portion with the fifth punch in a state where the peripheral portion of the flange is sandwiched between the fixed die and the fourth punch. Thus, a flange extending portion that extends to the extending flange portion may be formed.

  Furthermore, in order to solve the above problems, according to another aspect of the present invention, there is provided a burring molded product formed by burring of a workpiece and having a cylindrical stretch flange portion, the stretch flange portion and the stretch. The corner part formed by the flange peripheral part around the flange part is provided with a burring molded product having a plate thickness larger than that of the stretch flange part and the workpiece.

  In order to solve the above problems, according to another aspect of the present invention, there is provided a burring molded product formed by burring of a workpiece and having a cylindrical stretch flange portion, the stretch flange portion and the stretch. A burring molded article is provided in which the outside of the corner formed by the flange periphery around the flange is substantially perpendicular.

In the burring molded product, the curvature radius R1 inside the corner portion, the curvature radius R2 outside the corner portion, the stretch flange portion of the workpiece, and the plate thickness t of the workpiece satisfy the relationship of the following formula (1). You may shape | mold.
R2 ≦ R1 + t (1)

  Moreover, the plate | board thickness of the stretch flange part may be made larger than the plate | board thickness of a workpiece.

  The burring molded product may further include a flange extending portion in which the extending flange portion extends on the opposite side to the flange peripheral portion.

  The burring molded product may further include an inwardly extending portion in which a flange peripheral portion extends and extends toward the inside of the flange portion.

  As described above, according to the present invention, the corner portion can be freely formed.

It is a schematic sectional drawing which shows the structure of the burring processing apparatus which concerns on the 1st Embodiment of this invention with the operation | movement at the time of burring, Comprising: The state before the start of burring is shown. It is a schematic sectional drawing which shows the structure of the burring processing apparatus which concerns on the same embodiment with the operation | movement at the time of burring, Comprising: The stretch flange part and the outer side area | region are shown in the shape. It is a schematic sectional drawing which shows the structure of the burring apparatus which concerns on the same embodiment with the operation | movement at the time of burring, Comprising: The flange marginal area | region and the corner part are shown in the shape. It is a schematic sectional drawing which shows the structure of the burring processing apparatus which concerns on the same embodiment with the operation | movement at the time of burring, Comprising: The state which shape | molded the corner part at substantially right angle is shown. 3 is a partially enlarged portion of a region A in FIG. FIG. 4 is a partial enlarged portion of a region A in FIG. 3. FIG. 5 is a partial enlarged portion of a region A in FIG. 4. It is explanatory drawing which shows an example of the shape of the corner part in the cross section of the molded article shape | molded by the burring processing apparatus which concerns on the same embodiment, Comprising: The plate | board thickness of a corner part is larger than the plate | board thickness of a stretch flange part and a workpiece An example of molding to be large will be shown. It is explanatory drawing which shows an example of the shape of the corner part in the cross section of the molded product shape | molded by the burring processing apparatus which concerns on the same embodiment, Comprising: The example by which the outer side of the corner part was shape | molded at substantially right angle is shown. It is a schematic perspective view which shows an example of the burring molded product shape | molded by the burring processing apparatus which concerns on the same embodiment. It is explanatory drawing which shows an example of the molded article shape | molded by the press work which concerns on the 2nd Embodiment of this invention. It is a schematic sectional drawing which shows the structure of the press work apparatus which concerns on the same embodiment with the operation | movement at the time of press work, Comprising: The initial state of the press work which enlarges an extension flange part is shown. It is a schematic sectional drawing which shows the structure of the press work apparatus which concerns on the same embodiment with the operation | movement at the time of press work, Comprising: The state after the thickness increase of an extending flange part is shown. It is a schematic perspective view which shows an example of the molded article shape | molded by the press work which concerns on the 3rd Embodiment of this invention. It is a schematic sectional drawing which shows the structure of the press work apparatus which concerns on the same embodiment with the operation | movement at the time of press work, Comprising: The initial state of the press work which enlarges an extension flange part is shown. It is a schematic sectional drawing which shows the structure of the press work apparatus which concerns on the same embodiment with the operation | movement at the time of press work, Comprising: The state after the thickness increase of an extending flange part is shown. It is a schematic perspective view which shows the modification of the molded product shape | molded by the press work apparatus which concerns on the embodiment.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

(1. First embodiment: increase in the thickness of the corner)
(1-1. Operation of burring apparatus)
First, based on FIGS. 1-7, the burring process using the burring apparatus 100 which concerns on the 1st Embodiment of this invention is demonstrated. 1 to 4 are schematic cross-sectional views showing the configuration of the burring apparatus according to this embodiment together with the operation during burring. FIGS. 5-7 is the elements on larger scale which show the processing state of the workpiece 10 in the area | region A of FIGS.

  1 to 4, the burring apparatus 100 includes a die 110 and a punch 120. The die 110 includes a fixed die 111 and a movable die (pad) 113. The punch 120 includes a fixed punch 121, an outer movable punch (pad) 123, and an inner movable punch (pad) 127.

  As shown in FIG. 1, the workpiece 10 has a flat plate shape at the start of burring in the present embodiment. A prepared hole 12 is formed in advance in the workpiece 10 at a position where an elongated flange portion is formed by burring. The pilot hole 12 is formed by punching or cutting, for example.

  The fixed die 111 has a protruding portion 111 a having a shape corresponding to the inner surface shape of the stretch flange portion formed on the workpiece 10. Around the protrusion 111a, a movable die that is provided so as to be movable in the protrusion direction of the protrusion 111a with respect to the base 111b of the fixed die 111 and supports the flange periphery around the stretch flange part of the burring molded product 113 is provided. The movable die 113 is supported by a cushion 115 connected to the upper surface of the base portion 111 b of the fixed die 111 so that the upper surface of the movable die 113 contacts the workpiece 10.

  On the other hand, the punch 120 includes an outer movable punch 123 in contact with the outer peripheral region of the workpiece 10 and an inner movable punch 127 provided on the inner side of the outer movable punch 123 and in contact with the flange peripheral region and the extending flange portion. The fixed punch 121 is movably fixed to the fixed punch 121 by cushions 125 and 129, respectively. At this time, the inner movable punch 127 is supported at a position retracted from the outer movable punch 123 (that is, farther from the workpiece 10 and the die 110). In addition, the fixed punch 121 has a fitting portion 121 a that fits with the protruding portion 111 a of the die 110 on the inner side of the inner movable punch 127. In the state of FIG. 1, the outer movable punch 123 sandwiches the workpiece 10 between the outer region of the workpiece 10 and the upper surface of the movable die 113.

  When the punch 120 is pressed toward the die 110 after the press work is started, the cushion 115 of the die 110 is first contracted, and the movable die 113 is in contact with the outer movable punch 123 in the outer region of the workpiece 10. Is pushed into the base part 111b side of the die 110. At this time, the cushions 125 and 129 of the punch 120 do not contract. Therefore, the punch 120 is pushed into the base portion 111b of the die 110 while maintaining the positional relationship in which the inner movable punch 127 is retracted from the outer movable punch 123. That is, the inner movable punch 127 is pushed into the base portion 111 b of the die 110 later than the outer movable punch 123.

  When the punch 120 is pushed into the fixed die 111 while being sandwiched between the movable die 113 and the outer movable punch 123, the peripheral portion of the prepared hole 10 of the workpiece 10 extends along the protrusion 111a of the fixed die 111. It expands in the radial direction while being stretched in the pushing direction of the punch 120. As shown in FIGS. 2 and 5, when the movable die 113 bottoms into the base portion 111 b, the extending flange portion 13 protruding from the edge of the prepared hole 12 is formed. Hereinafter, the hollow portion of the elongated flange portion 13 formed by expanding the diameter of the pilot hole 12 is referred to as a burring hole 14.

  In the present embodiment, the stretch flange portion 13 is restrained by the inner movable punch 127 and the side surface 111 c of the protrusion 111 a of the fixed die 111. That is, in the burring apparatus 100, the inner movable punch 127 is arranged so that the distance between the protrusion 111 a and the side surface 111 c substantially matches the plate thickness of the workpiece 10. Further, the inner movable punch 127 is delayed from the outer movable punch 123 when the movable die 113 is pushed into the outer movable punch 123 and bottoms out on the upper surface of the base portion 111b of the fixed die 111. Since it is pushed into the base part 111 b side, a tapered part 17 exists between the outer side region 15 a of the workpiece 10 and the extending flange part 13.

  Next, when the punch 120 is further pushed into the die 110 side, as shown in FIGS. 3 and 6, the cushion 125 of the punch 120 contracts and the inner movable punch 127 is pushed into the base portion 111 b side of the fixed die 111. And catch up with the outer movable punch 123. The end surface of the inner movable punch 127 and the end surface of the outer movable punch 123 are substantially flush with each other, and the inner movable punch 127 moves the workpiece 10 (tapered portion 17) between the upper surface of the base portion 111b of the fixed die 111. It will be in a state of being sandwiched. Thereby, the flange edge region 15b on the burring hole 14 side from the outer edge region 15a of the workpiece 10 and the corner portion 18 formed by the flange edge region 15b and the extending flange portion 13 are formed. In the following description, the outer edge region 15a and the flange edge region 15b are collectively referred to as the flange peripheral portion 15 of the workpiece 10. The flange peripheral portion 15 refers to a portion other than the stretch flange portion 13 in the workpiece 10.

  Here, as apparent from FIGS. 2 and 3, in the cross section of the workpiece 10, the length of the tapered portion 17 is longer than the combined length of the flange edge region 15 b and the corner portion 18. Therefore, according to the burring apparatus 100 according to the present embodiment, the corner portion 18 is thickened, that is, the corner portion 18 is formed so as to have a plate thickness larger than that of the elongated flange portion 13 and the workpiece 10. Is possible.

  As an additional step, as shown in FIG. 4, after the step shown in FIG. 3, the punch 120 may be further pushed toward the base portion 111 b of the fixed die 111. As a result, the cushions 125 and 129 of the punch 120 contract, and the fitting portion 121a of the fixed punch 121 is pushed into the protruding portion 111a of the die 110. Here, the end surface of the fitting portion 121 a of the fixed punch 121 is formed with a concave portion 121 b into which the protruding portion 111 a of the fixed die 111 enters, and the end surface 121 c of the concave portion 121 b is extended by the pushing of the punch 120. Abutting on the end face 19. Then, by further pressing the punch 120, as shown in FIGS. 4 and 7, the end surface 121c of the fixed die 111 extends and the end surface 19 of the flange portion 13 is pressed, and the material of the workpiece 10 is moved. In the state of FIG. 6, a slight gap existing between the protruding portion 111 a of the fixed die 111, the base portion 111 b and the corner portion 18 of the workpiece 10 is filled. Thereby, the corner part 18 can be further thickened. In the example of FIG. 4, the outside of the corner portion 18 is formed at a substantially right angle.

(1-2. Features of molded products)
8 and 9 are explanatory diagrams illustrating an example of the shape of the corner portion in the cross section of the molded product molded by the burring apparatus according to the first embodiment of the present invention. FIG. 8 shows an example in which the corner portion 18 is formed to have a plate thickness larger than that of the elongated flange portion 13 and the workpiece 10 (the flange edge region 15b and the outer edge region 15). FIG. 9 shows an example in which the outside of the corner portion 18 is formed substantially at a right angle.

  As described above, in the burring process using the burring apparatus 100 according to the present embodiment, the stretch flange portion 13 and the outer edge region 15a of the workpiece 10 are formed on the workpiece 10, and then the stretch flange portion 13 and The corner portion 18 is formed by crushing the tapered portion 17 between the workpiece 10 and the outer side region 15 a with the inner movable punch 127. For this reason, the material does not flow between the elongated flange portion 13 and the flange peripheral portion 15, and the radius of curvature outside the corner portion 18 can be reduced, or the outside of the corner portion 18 can be made substantially perpendicular. It is.

For example, as shown in FIG. 8, the plate thickness tc of the corner portion 18 of the workpiece 10 can be formed to be larger than the plate thickness t before the workpiece 10 is processed. That is, the corner portion 18 is thickened. Here, the plate thickness t ₁ of the flange peripheral portion 15 is assumed to be equal to the plate thickness t before the workpiece 10 is processed. Further, the plate thickness t ₂ of the stretch flange portion 13 is a member formed by stretching a material by burring processing and is likely to be smaller than the plate thickness t ₁ of the flange peripheral portion 15.

  In the cross section of the workpiece 10 formed by the burring apparatus 100 according to the present embodiment, the outer radius of curvature R2 of the corner portion 18 is set to the inner radius of curvature R1 by the thickness t before the workpiece 10 is processed. It is smaller than that added (R2 <R1 + t). In particular, as shown in FIG. 8, it is possible to make the outer radius of curvature R2 smaller than the inner radius of curvature R1 (R2 <R1). Further, when the corner portion 18 has a plate thickness t before the workpiece 10 is processed, the outer curvature radius R2 is the sum of the inner curvature radius R1 and the plate thickness t before the workpiece 10 is processed. (R2 = R1 + t). From the above, in this embodiment, increasing the thickness of the corner portion 18 means that the outer radius of curvature R2 of the corner portion 18 is a value obtained by adding the plate thickness t before processing the workpiece 10 to the inner radius of curvature R1. Is equivalent to When the plate thickness tc of the corner portion 18 is smaller than the plate thickness t before the workpiece 10 is processed, the outer radius of curvature R2 of the corner portion 18 is set to the inner radius of curvature R1 of the workpiece 10. It becomes larger than the sum of the thickness t before processing (R2> R1 + t).

  Specifically, for example, when the plate thickness t before processing the workpiece 10 is 5 mm, the curvature radius R2 outside the corner portion 18 is set to 0.5 mm (10% of the plate thickness t), and the curvature radius on the inside is set. If R1 is 7.5 mm (1.5 times the plate thickness t), burring can be performed without causing folding. Note that, as in the example shown in FIG. 9, the outer side of the corner portion 18 can be formed at a right angle, so the radius of curvature R2 may be smaller than 0.5 mm. Further, in the relationship with the prior art as described above, although the advantage of this embodiment is remarkable when the curvature radius R2 is reduced, the curvature radius R2 outside the corner portion 18 is large, so that Since the application is not hindered, the radius of curvature R2 may be larger than 0.5 mm. As for the curvature radius R1 inside the corner portion 18, if the curvature radius R2 is too large with respect to the curvature radius R2, there is a possibility that wrinkles due to material folding or the like may occur. When it is in the range as in the example, it is possible to carry out the burring process without causing wrinkles.

  In the example shown in FIG. 9, the outer side of the corner portion 18 is formed at a substantially right angle in the cross section of the workpiece 10. In the present specification, when “the outside of the corner portion 18 is substantially right angle”, the radius of curvature of the outside of the corner portion 18 is not limited to the case where the outside of the corner portion 18 is strictly right. The case of being small and close to 0 is also included. In this case, the inside of the corner portion 18 can also be formed at a substantially right angle. However, from the viewpoint of avoiding stress concentration on the corner portion 18, the inside of the corner portion 18 has a certain amount (not close to 0). It is desirable to provide a radius of curvature R1. In this case, it can be understood that the outer radius of curvature of the corner portion 18 is smaller than the inner radius of curvature R1 plus the plate thickness t of the workpiece 10 before processing. Therefore, in the example shown in FIG. 9, it can be said that the corner portion 18 is thickened.

  FIG. 10 is an example of a burring product 50 molded by the burring apparatus 100 according to the present embodiment. An axisymmetric burring molded product 50 shown in FIG. 10 includes an elongated flange portion 53 and a flange peripheral portion 55. The stretch flange portion 53 has a cylindrical shape, and a burring hole 54 is formed. The cross section of the workpiece 10 shown in FIGS. 8 and 9 corresponds to the cross section taken along the line BB of the burring molded product 50 of FIG. The burring molded product 50 is characterized in that the corner portion 58 is thickened or the outside of the corner portion 58 is substantially perpendicular. That is, the inner peripheral surface of the stretch flange portion 53 is substantially flush to the flange peripheral portion 55 side. Therefore, when a thread groove is formed in the burring hole 54, the area in which the thread groove is formed can be increased, so that the coupling strength with the screw can be increased.

(1-3. Summary)
In the first embodiment of the present invention described above, in the burring process of the workpiece 10 using the burring apparatus 100, the inner movable punch 127 is delayed from the outer movable punch 123 and the base portion of the fixed die 111 is delayed. By being pushed into the side of 111b, the taper part 17 is formed between the stretch flange part 13 and the outer side area | region 15a of the to-be-processed material 10. FIG. The length of the taper portion 17 is longer than the combined length of the flange peripheral portion 15 and the corner portion 18 finally formed. Therefore, by forming the corner portion 18 by expanding the tapered portion 17, the corner portion 18 is increased in thickness without causing the material to flow between the stretch flange portion 13 and the outer region 15 a of the workpiece 10. be able to. Therefore, in the present embodiment, the radius of curvature outside the corner portion 18 can be reduced or the outside of the corner portion 18 can be made substantially right-angled compared to the prior art. Further, only the corner portion 18 can be increased without increasing the thickness of the stretch flange portion 13 and the flange peripheral portion 15.

  Further, in the burring apparatus 100 according to the present embodiment, the base portion of the fixed die 111 is delayed from the outer movable punch 123 by the action of the cushion 125 in the series of pressing steps for pressing the punch 120. It is pushed into the 111b side. Thereby, the corner portion 18 can be freely formed. Thus, the burring apparatus 100 according to the present embodiment may be uniaxial, and a multi-axis burring apparatus that presses a plurality of portions of the punch independently of each other is not required.

  In the above-described example, the burring process is started from a state in which the workpiece 10 is flat as shown in FIG. 1, but the present invention is not limited to such an example. For example, the shape of the workpiece 10 is not particularly limited, and burring can be performed on workpieces other than flat plates. Further, in the burring molded product 50 shown in FIG. 10, the shape of the stretch flange portion 53 in plan view (that is, the shape of the burring hole 54) is circular, but the present invention is not limited to such an example. It may be oval or polygonal. Furthermore, although each process of the burring method according to the present embodiment described based on FIGS. 1 to 4 was performed by the burring apparatus 100 as a series of processes, the present invention is not limited to such an example, and each process is performed. You may carry out and share with several processing apparatuses.

(2. Second Embodiment: Increased Thickness of Stretch Flange)
Next, a second embodiment of the present invention will be described. In the present embodiment, a process of further pressing the burring molded product molded by the burring processing method according to the first embodiment and molding a molded product having a thick stretch flange portion is added. . By press-molding a molded product having a stretched flange portion thickened using a burring molded product molded by the burring method according to the first embodiment, the stretched flange portion is formed without overlapping the internal corner surfaces. Can increase the thickness. Below, the process of increasing the thickness of the stretch flange portion will be described on the assumption that the burring molded product molded by the burring method according to the first embodiment is used.

  FIG. 11 is an explanatory view showing an example of a molded product 60A formed by press working according to the present embodiment. A molded product 60 </ b> A shown in FIG. 11 is a molded product including an elongated flange portion 63 and a flange peripheral portion 65. This molded product 60A is molded by, for example, pressing a burring molded product 50 having a small radius of curvature outside the corner portion or a substantially right angle as shown in FIG. .

  The configuration of the press working apparatus 200 for increasing the thickness of the stretch flange portion 63 according to this embodiment is shown in FIGS. 12 and 13. FIG. 12 is a schematic cross-sectional view showing an initial state of press working for increasing the thickness of the stretch flange portion. FIG. 13 is a schematic cross-sectional view showing a state after the thickening of the stretch flange portion. Referring to FIGS. 12 and 13, the press working apparatus 200 includes a die 210 and a punch 220. The die 210 is a fixed die. The punch 220 includes a fixed punch 221 and a movable punch (pad) 223.

  As shown in FIG. 12, at the start of press working in the present embodiment, the workpiece 20 is, for example, a burring molded product molded according to the first embodiment, and has a small radius of curvature outside the corner portion. Or it is a substantially right angle. For example, the workpiece 20 is the burring molded product 50 shown in FIG. 10, and in this case, a molded product 60 </ b> A in which the stretch flange portion 63 shown in FIG. . In addition, this invention is not limited to this example, The press work apparatus 200 can also shape | mold a burring molded product other than the shape shown in FIG.

  The die 210 has a protrusion 211 through which the burring hole 24 of the workpiece 20 is inserted. The protrusion 211 is formed corresponding to the shape of a molded product manufactured from the workpiece 20. Accordingly, the outer diameter of the protruding portion 211 is formed smaller than the inner diameter of the stretch flange portion 23 of the workpiece 20 (that is, the inner diameter of the burring hole 24). The workpiece 20 is inserted into the protruding portion 211 of the die 210 from the flange peripheral portion 25 side through the burring hole 24 and is installed on the base portion 213 of the die 210. At this time, on the inner side of the stretch flange portion 23 of the workpiece 20, there is a space for increasing the thickness by the press work.

  On the other hand, the punch 220 is arranged so that the movable punch 223 contacts the flange peripheral portion 25 of the workpiece 20. At this time, the movable punch 223 presses the workpiece 20 by the cushion 225 connected to the fixed punch 221, and sandwiches the flange peripheral portion 25 of the workpiece 20 with the upper surface of the base portion 213 of the die 210. doing. The punch 220 has a fitting portion 221 a that is provided on the inner side of the movable punch 223 and fits with the protruding portion 211 of the die 210. The end surface of the fitting portion 221a of the fixed punch 221 is formed with a recess 221b into which the protruding portion 211 of the die 210 enters. The end surface 221 c of the recess 221 b faces the end surface 29 of the stretch flange portion 23.

  When the press processing by the press processing apparatus 200 is started, as shown in FIG. 13, the cushion 225 provided between the fixed punch 221 and the movable punch 223 contracts, and the fixed punch 221 moves toward the die 210 side. . Thereby, the end surface 29 of the extending flange portion 23 is pushed in by the end surface 221c of the fitting portion 221a of the fixed punch 221, and the material constituting the extending flange portion 23 of the workpiece 20 is in contact with the protruding portion 211 of the die 210. It flows into the space that exists in between and fills that space. In this way, as shown in FIG. 13, the stretch flange portion 23 of the workpiece 20 is made thicker than before the press work, and the radius of curvature outside the corner portion 28 after the press work is made small as before the press work. Alternatively, it can be a substantially right angle.

  Here, the molded product molded according to the present embodiment is formed by pressing the molded product having a small radius of curvature or a substantially right angle outside the corner portion molded by the above-described embodiment with the press working apparatus 200. It is obtained with. When the radius of curvature outside the corner portion of the workpiece is large and the plate thickness of the corner portion is thin, when the end face of the stretch flange portion is pressed by the press processing apparatus 200, the material of the stretch flange portion and the flange peripheral portion flows. As a result, wrinkles such as folding will occur inside the corner. The folded part is the part where the inner surfaces of the stretch flange part and the flange peripheral part are in contact with each other and overlap, and the overlap between the stretch flange part and the flange peripheral part is easy to open, so compared to other parts Strength decreases. In addition, the folded portion also becomes a factor of fatigue failure.

  Therefore, as in this embodiment, when a burring molded product having a small radius of curvature outside the corner portion or a substantially right angle is used as the workpiece, the flange peripheral portion 25 of the workpiece 20 is the base of the die 210. Since the material of the corner portion 28 flows while being sandwiched between the portion 213 and the movable punch 223, the space between the protruding portion 211 of the die 210 can be filled without causing folding. Therefore, no bending occurs inside the corner portion 28, and the radius of curvature outside the corner portion 28 can be made small or substantially perpendicular as before pressing.

  In the second embodiment of the present invention described above, the outer side of the corner portion formed in the first embodiment as the work material 20 in the press work of the work material 20 using the press working apparatus 200. A burring molded product having a small curvature radius or a substantially right angle is used. Then, a material is applied between the stretch flange portion 23 and the flange peripheral portion 25 by applying a load to the end surface 29 of the stretch flange portion 23 in a state where the flange peripheral portion 25 of the workpiece 20 is sandwiched by the press working device 200. In addition to increasing the thickness of the elongated flange portion 23 without causing the fluid to flow, the radius of curvature outside the corner portion 28 can be reduced or the outside of the corner portion 28 can be made substantially perpendicular to the conventional technique. The rear corner portion 28 can also be increased in thickness.

(3. Third embodiment: extrusion processing)
(3-1. Extrusion of stretch flange part)
Next, a third embodiment of the present invention will be described. In the present embodiment, a process of further pressing the burring molded product molded by the burring processing method of the first embodiment and molding the molded product with the extended flange portion extended is added. By press-molding the burring molded product molded according to the first embodiment, the stretch flange portion can be extended and the stretch flange portion can be extended without overlapping the internal corner surfaces. Below, the process of extending an extending flange part is demonstrated on the assumption that the burring molded product shape | molded by 1st Embodiment is used.

  FIG. 14 is an explanatory view showing an example of a molded product 60B formed by press working according to the present embodiment. A molded product 60B shown in FIG. 14 is a molded product including an elongated flange portion 63, a flange peripheral portion 65, and a flange extending portion 67 in which the elongated flange portion 63 extends from the corner portion side. This molded product 60B is also formed by, for example, further pressing the burring molded product 50 shown in FIG. 10 having a small curvature radius outside the corner portion or having a substantially right angle by a press working apparatus described below. The

  The structure of the press processing apparatus 300 for extending the stretch flange part 63 according to the present embodiment is shown in FIGS. FIG. 15 is a schematic cross-sectional view showing an initial state of press working for extending the stretch flange portion. FIG. 16 is a schematic cross-sectional view showing a state after the extension flange portion is extended. Referring to FIGS. 15 and 16, the press working apparatus 300 includes a die 310 and a punch 320. The die 310 includes an elongated flange fixing die 311, a flange peripheral fixing die 313, and a movable die (pad) 315. The punch 320 includes a fixed punch 321 and a movable punch (pad) 323.

  As shown in FIG. 15, at the start of press working in the present embodiment, the workpiece 20 is a burring molded product formed by the burring method of the first embodiment, as in the second embodiment. The radius of curvature outside the corner is small or substantially perpendicular. For example, the workpiece 20 is the burring molded product 50 shown in FIG. 10, and in this case, a molded product 60 </ b> B in which the stretch flange portion 63 shown in FIG. Is formed. In addition, this invention is not limited to this example, The press work apparatus 300 can shape | mold burring molded articles other than the shape shown in FIG.

  The die 310 includes an elongated flange fixing die 311 that is a protrusion through which the burring hole 24 of the workpiece 20 is inserted, and a flange peripheral fixing die 313 and a movable die 315 that support the flange peripheral portion 25 of the workpiece 20. It is configured. The stretch flange portion 23 of the workpiece 20 is sandwiched between the side surface of the stretch flange fixing die 311 and the side surface of the movable punch 323. The flange periphery fixed die 313 and the movable die 315 are provided so as to recede from the elongated flange fixed die 311 (that is, on the side opposite to the punch 320). The movable die 315 is provided at a position corresponding to the extending flange portion 23, and is connected to the flange peripheral fixing die 313 by a cushion 317 so as to be movable in the pressing direction of the punch 320. The flange peripheral fixed die 313 is provided outside the movable die 315 and sandwiches a part of the flange peripheral portion 25 of the workpiece 20 together with the movable punch 323. The workpiece 20 extends from the flange peripheral portion 25 side through the burring hole 24 and is inserted into the flange fixed die 311, and is installed on the flange peripheral fixed die 313 and the movable die 315. At this time, the movable die 315 is pushed by the flange peripheral portion 25 of the workpiece 20 to a position where the flange peripheral portion 25 contacts the flange peripheral fixed die 313.

  On the other hand, the punch 320 is disposed so that the movable punch 323 contacts the flange peripheral portion 25 of the workpiece 20. At this time, the movable punch 323 presses the workpiece 20 by the cushion 325 connected to the fixed punch 321, and sandwiches the flange peripheral portion 25 of the workpiece 20 between the upper surface of the flange peripheral fixing die 313. Yes. In addition, the punch 320 has a fitting portion 321 a that is provided on the inner side of the movable punch 323 and fits with the elongated flange fixing die 311. The end surface of the fitting portion 321a of the fixed punch 321 is formed with a recess 321b into which the elongated flange fixing die 311 enters. The end surface 321 c of the recess 321 b faces the end surface 29 of the stretch flange portion 23.

When the press processing by the press processing apparatus 300 is started, as shown in FIG. 16, the cushion 325 provided between the fixed punch 321 and the movable punch 323 contracts, and the fixed punch 321 moves toward the die 310 side. . This
The end surface 29 of the extending flange portion 23 is pushed in by the end surface 321c of the fitting portion 321a of the fixed punch 321, and the material constituting the extending flange portion 23 of the workpiece 20 pushes in the movable die 315 and contracts the cushion 317. Then, instead of the movable die 315, it moves so as to fill the space between the elongated flange fixing die 311 and the flange peripheral fixing die 313. In this way, as shown in FIG. 16, the extending flange portion 23 of the workpiece 20 can be extended more than before the press working.

  At this time, the workpiece 20 after the press working includes a first inner corner portion 28a formed by the outer surface of the elongated flange portion 23 and the upper surface of the flange peripheral portion 25, and the outer surface of the flange extending portion 27. And a second inner corner portion 28b formed by the lower surface of the flange peripheral portion 25. Here, similarly to the second embodiment, the molded product formed by the present embodiment has a small radius of curvature outside the corner portion formed by the burring method of the first embodiment described above, or a substantially right angle. Can be obtained by pressing the formed product with the press working apparatus 300. If the radius of curvature outside the corner portion of the workpiece is large and the plate thickness of the corner portion is thin, when the end face of the stretch flange portion is pressed by the press processing device 300, the material of the stretch flange portion and the flange peripheral portion is changed. It will flow and wrinkles such as folding will occur in the first inner corner portion 28a. The folded portion is lower in strength than the other portions and causes fatigue failure.

  On the other hand, when a burring molded product having a small radius of curvature outside the corner portion or a substantially right angle is used as a workpiece as in this embodiment, the flange peripheral portion 25 of the workpiece 20 is a flange. The material of the corner portion 28 flows while pressing the movable die 315 while being sandwiched between the peripheral fixed die 313 and the movable punch 323. Therefore, folding does not occur inside the corner portion 28. In addition, the second inner corner portion 28b, like the first inner corner portion 28a, has a certain amount (not close to 0) inside the corner portion 28 from the viewpoint of avoiding stress concentration on the corner portion 28. It is desirable to provide a radius of curvature. For example, the second inner corner portion 28b may have a radius of curvature similar to that of the first inner corner portion 28a.

  In the third embodiment of the present invention described above, the outer side of the corner portion formed in the first embodiment as the work material 20 in the press work of the work material 20 using the press working device 300. A burring molded product having a small curvature radius or a substantially right angle is used. Then, a load is applied to the end surface 29 of the stretch flange portion 23 in a state where the flange peripheral portion 25 of the workpiece 20 is sandwiched by the press working device 300. Thereby, even if it does not flow a material between the stretch flange part 23 and the flange surrounding part 25, the stretch flange part 23 can be extended, and it does not generate | occur | produce in the 1st inner corner part 28a. .

(3-2. Modification: Extruding the flange periphery)
In the press working apparatus 300 according to the present embodiment shown in FIGS. 15 and 16, the extending flange portion 23 of the burring molded product is extruded to the opposite side to the flange peripheral portion 25 to form the flange extending portion 27. As shown in FIG. 17, it is also possible to form the inwardly extending portion 69 by extruding the flange peripheral portion 25 of the burring molded product to the burring hole 64 side. In this case, for example, in the press working apparatus 200 according to the second embodiment shown in FIG. 12, the outer diameter of the protrusion 211 is substantially the same as that of the burring hole 24, and the flange peripheral portion 25 is extended to the protrusion 211. A recessed portion is formed. Then, when the punch 220 of the press working device 200 is pushed into the die 210 side, the end surface 221c of the fixed punch 221 extends and presses the end surface 29 of the flange portion 23, and the material of the corner portion flows to form the flange peripheral portion 25. The recessed portion is filled, and a molded product 60C as shown in FIG. 17 can be formed.

  The molded product 60 </ b> C shown in FIG. 17 is also subjected to press processing using a press processing device, which is a burring molded product having a small radius of curvature or a substantially right angle outside the corner formed by the burring method according to the first embodiment. Can be obtained. If the radius of curvature outside the corner of the workpiece is large and the corner is thin, when the end face of the stretch flange is pressed by the press machine, the material in the stretch flange and the flange periphery flows. This causes wrinkles such as folding inside the corner portion. The folded portion is lower in strength than the other portions and causes fatigue failure.

  On the other hand, when a burring molded product having a small radius of curvature outside the corner portion or a substantially right angle is used as a workpiece as in the present embodiment, the flange peripheral portion of the workpiece is a die and a punch. When the end face of the extending flange portion is pressed in the state of being sandwiched between the two, the material of the corner portion flows, and the concave portion formed on the burring hole side is filled. Therefore, even in this case, the corner portion formed by the outer surface of the stretch flange portion and the flange peripheral portion does not fold.

(4. Summary)
According to the first embodiment of the present invention described above, in the burring of the workpiece using the burring apparatus, after the tapered portion is formed between the stretch flange portion and the flange peripheral portion, the tapered portion is formed. Press to open the corners. Thereby, even if it is not made to flow a material between an elongate flange part and a flange circumference part, a corner part can be thickened. Therefore, the radius of curvature outside the corner portion can be reduced or the outside of the corner portion can be made substantially perpendicular to the prior art. Further, according to the first embodiment of the present invention, instead of forming the radius of curvature outside the corner from the flat plate in one step, or forming it at a substantially right angle, the shape outside the corner is pushed in stepwise. By molding the burring, it is possible to perform burring with a smaller load than in the prior art. Therefore, burring molding of a steel material having high strength can be processed without causing cracks or the like during molding. The material that can be formed by the burring method according to the first embodiment of the present invention includes aluminum and the like in addition to steel.

  Further, according to the second and third embodiments of the present invention, the burring molding with a small radius of curvature or a substantially right angle outside the corner portion, which is molded by the burring molding apparatus of the first embodiment. The product is used as the second workpiece and further pressed to form a molded product of another shape. By using a molded product with a small curvature radius or a substantially right angle outside the corner portion as the second workpiece, the extension flange portion is increased in thickness, and the extension flange portion or the flange peripheral portion is extended by pressing. In this case, it is possible to prevent wrinkles such as folding inside the corner portion.

  Furthermore, the molded product molded by the press molding apparatus according to the second and third embodiments of the present invention is a molded product having a complicated shape, and conventionally, a plurality of components are connected by welding or the like. It was common to form. However, by combining the burring molding using the burring molding apparatus of the first embodiment and the press molding using the press molding apparatus of the second embodiment and the third embodiment, a molded product having a complicated shape. Can be manufactured as a single component. As a result, the number of components can be reduced, the component weight can be reduced, and the manufacturing cost can be reduced.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

10, 20 Workpiece material 12 Pilot hole 13, 23 Stretch flange portion 14, 24 Burring hole 15, 25 Flange peripheral portion 15a Outer region 15b Flange edge region 17 Tapered portion 18, 28 Corner portion 19, 29 End surface 27 Flange extension Installation part 50 Burring molded product 53 Stretch flange part 54 Burring hole 55 Flange peripheral part 58 Corner part 60A, 60B, 60C Molded part 63 Stretch flange part 64 Burring hole 65 Flange peripheral part 67 Flange extension part 69 Inward extension part 100 Burring process Device 110 Die 111 Fixed die 113 Movable die 115, 125, 129 Cushion 120 Punch 121 Fixed punch 121a Fitting portion 123 Outer movable punch 127 Inner movable punch 200, 300 Press working device 210, 310 Die 2 First protrusion 213 base portion 220 and 320 punches 221 and 321 fixed punch 221a, 321a engagement part 221b, 321b recess 223, 323 movable punch 225,317,325 cushion 311 flange fixed die 313 the flanges around the fixed die 315 movable die

Claims (16)

A burring apparatus for burring a workpiece to obtain a molded product having a cylindrical stretch flange portion,
A fixed die having a flat part and a protruding part protruding from the flat part and corresponding to the shape of the inner surface of the stretch flange part;
A movable die provided so as to be movable in the protruding direction of the protruding portion with respect to the fixed die, and supporting a flange peripheral portion around the extending flange portion;
A die including
Between the movable die, among the flange peripheral portion, a first punch for sandwiching an outer side region located on the outer side rather than a flange peripheral region located on a side edge of the elongated flange portion,
The movable die that is in contact with the flat portion of the fixed die is pushed later than the first punch, restrains the extending flange portion with the side surface of the protrusion, and the movable die A second punch for forming a corner portion formed by the flange edge region and the extending flange portion by sandwiching the flange edge region of the flange peripheral portion therebetween,
Including a punch,
A burring apparatus. The workpiece is a flat plate having a pilot hole at the start of the burring process,
The first punch and the second punch are formed by pressing the plate-shaped workpiece into the flat portion of the fixed die in a state where the second punch is retracted from the first punch. The burring apparatus according to claim 1, wherein the outer peripheral region of the stretch flange portion and the flange peripheral portion is formed.   3. The burring apparatus according to claim 1, wherein the corner portion is formed to have a plate thickness larger than that of the stretch flange portion and the workpiece.   The punch is brought into contact with an end face of the extending flange portion on the opposite side to the corner portion, and a third punch that is pushed toward the flat portion of the fixed die after the corner portion is formed by the second punch. The burring apparatus according to claim 1, further comprising:   The burring apparatus according to claim 4, wherein an outer side of the corner portion is formed at a substantially right angle. A burring method for burring a workpiece to obtain a molded product having a cylindrical stretch flange portion,
The portion corresponding to the extending flange portion is made to correspond to the protruding portion protruding from the flat portion of the fixed die, and the flange peripheral portion around the extending flange portion can be moved in the protruding direction of the protruding portion with respect to the fixed die. Placing the workpiece on the die so as to correspond to the movable die;
In a state where the outer edge region located on the outer side is sandwiched between the first punch and the movable die, the flange peripheral region located on the edge of the extending flange portion of the flange peripheral portion. Pressing the second punch that restrains the stretch flange portion between the punch and the side surface of the protrusion until the movable die contacts the flat portion of the fixed die; and
In a state in which the outer edge region is sandwiched between the movable die and the first punch that are in contact with the flat portion of the fixed die, the second punch is delayed from the first punch to the movable die. Pressing against the flange edge region and the step of forming a corner portion formed by the stretch flange portion,
Including a burring method.   After the corner portion is formed by the second punch, a step of pushing a third punch abutted against the end surface of the extending flange portion on the opposite side of the corner portion toward the flat portion of the fixed die. The burring method according to claim 6, further comprising: As a second workpiece, a molded article having the cylindrical elongated flange portion obtained by burring is used.
A shape corresponding to the shape of the second molded product, the second projection part into which the hollow portion of the stretch flange portion is inserted, and a second plane that supports the flange peripheral portion around the stretch flange A second die having a portion, a fourth punch for sandwiching the flange peripheral portion together with the second flat portion of the second die, and an end face of the extending flange portion, and the second molding Using a press molding apparatus having a fifth punch for molding a product,
A step of pressing the end face of the elongated flange portion with the fifth punch and molding the second molded product while the flange peripheral portion is sandwiched between the second flat portion and the fourth punch. The burring method according to claim 7, further comprising: The second protrusion of the press molding apparatus is formed with a smaller diameter than the inner diameter of the stretch flange portion,
9. The end face of the stretch flange portion is pushed in by the fifth punch in a state where the peripheral portion of the flange is sandwiched between the second flat portion and the fourth punch, and the stretch flange portion is thickened. The burring method described in 1. Of the second die of the press molding apparatus, the second flat surface portion that supports the flange peripheral portion supports a fixed die that supports a region other than the corner portion of the flange peripheral portion, and the corner portion. And a movable die movable in the extending direction of the extending flange portion,
With the flange periphery held between the fixed die and the fourth punch, the end face of the stretch flange portion is pushed in by the fifth punch, and the movable die is moved to extend to the stretch flange portion. The burring method according to claim 8, wherein a flange extending portion is formed. A burring molded product formed by burring processing of a workpiece and having a cylindrical stretch flange portion,
A corner portion formed by the stretch flange portion and a flange peripheral portion around the stretch flange portion is a burring molded product having a plate thickness larger than that of the stretch flange portion and the workpiece. A burring molded product formed by burring processing of a workpiece and having a cylindrical stretch flange portion,
A burring molded product, wherein an outer side of a corner portion formed by the stretch flange portion and a flange peripheral portion around the stretch flange portion is substantially a right angle. The curvature radius R1 inside the corner portion, the curvature radius R2 outside the corner portion, the stretch flange portion of the workpiece, and the plate thickness t of the workpiece satisfy the relationship of the following formula (1). The burring molded article according to claim 12.
R2 ≦ R1 + t (1)   The burring molded product according to claim 12 or 13, wherein a plate thickness of the stretch flange portion is larger than a plate thickness of the workpiece.   The burring molded article according to claim 12 or 13, further comprising a flange extending portion in which the extending flange portion extends on the opposite side to the flange peripheral portion. The burring molded product according to claim 12 or 13, further comprising an inwardly extending portion in which the flange peripheral portion extends toward the inner side of the elongated flange portion.

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