JP5632673B2 - Burring method - Google Patents

Description

  The present invention relates to a method for burring a metal plate-shaped workpiece and a projection forming mold for forming a projection on the workpiece in order to perform burring.

  Conventionally, when burring is performed on a plate-shaped workpiece, burring is performed after a pilot hole is previously machined in the workpiece (see, for example, Patent Documents 1 and 2).

  Further, burring is also performed without previously preparing a pilot hole in a work (see, for example, Patent Documents 3 and 4).

JP-A 63-160727 JP 2002-346682 A Japanese Patent Laid-Open No. 10-225729 JP 2005-28373 A

  As described in Patent Documents 1 and 2, when a burring is performed after a pilot hole has been previously machined in a workpiece, the protruding height dimension of the burring is obtained so that the number of threads necessary for tapping in the next process can be obtained. If it is going to be large, the tip side of the molded burring becomes thin and the tip surface becomes rough, which may cause cracks and the like.

  Therefore, as described in Patent Document 2, it is necessary to size the tip surface of the burring with a sleeve punch provided inside, and there is a problem that the configuration of the mold becomes more complicated.

  In the method described in Patent Document 3 in which burring is performed without previously preparing a pilot hole in a workpiece, when a convex portion is formed on the upper surface of a plate-shaped workpiece (first step), the outer diameter of the convex portion is almost the same. An equal concave portion is formed on the lower surface of the workpiece, and a concave portion is formed at the center of the convex portion, thereby forming an annular convex portion around the concave portion by backward extrusion (second step), and then hitting the bottom of the concave portion. A hole is formed by pulling out (third step), and then burring (fourth step) is performed (see FIGS. 1A to 1E of Patent Document 3). Therefore, in order to perform the burring process described in Patent Document 3, a mold is required for every four steps, and there is a problem that the number of molds is increased. There is a problem that it is difficult to form a larger number of threads in the processed part.

  The method described in Patent Document 4 is a method of forming a recess in a plate-shaped workpiece and punching out the bottom of the recess, so that only two types of molds are used, and the number of molds to be used is small. However, it is intended for a case where the burring height is three times or less of the plate thickness, and there is a problem in obtaining a larger number of threads when a screw is formed in the burring portion.

  In addition, conventionally, when performing a burring process by processing a pilot hole in a plate-shaped workpiece, for example, a pilot hole is processed in order to process, for example, an M3 screw hole in a stainless steel plate having a thickness of about 2 mm. When burring is performed, the diameter for punching the pilot hole becomes a small diameter of about 1 mm. Thus, when the punch diameter is smaller than the thickness of the workpiece, punching of the pilot hole becomes extremely difficult. Therefore, processing using a drill for processing the pilot hole or processing using laser light is unavoidable, and a processing machine separate from the punch press for punching plate-like workpieces is required. There is a problem of doing.

The present invention has been made in view of the conventional problems as described above, and is a method for performing burring processing on a plate-shaped workpiece, in which a male mold is added to a burring portion molding recess provided in a female mold. A part of the work is pressed and inserted by a pressure protrusion to form a protrusion in the work, and the tip of the pressure protrusion and the bottom of the burring part forming recess or the female die are provided to be movable up and down. Provided in the lifting body, the tip portion of the projection portion is crushed between the tip surface of the pressure projection portion inserted into the burring portion molding recess, and the thin portion is thinner than the cylindrical portion of the projection portion The inner peripheral surface of the projecting portion is shaved when the projecting portion is formed at the distal end portion of the projecting portion and the thin portion of the distal end portion is punched.

  According to the present invention, it is possible to perform burring without processing a pilot hole with a small diameter on a plate-like workpiece. And since the thin part thinner than the thickness of the cylindrical part of the projecting part is formed at the tip part of the projecting part formed to perform burring processing, this thin part is punched and processed beforehand. Compared with the case where the burring is performed by processing, the length of the protruding portion can be made longer. Moreover, since the thin portion is punched, punching for penetrating the protruding portion can be performed more easily.

It is a section explanatory view showing composition of a metallic mold concerning a 1st embodiment used for a burring processing method of the present invention. It is effect | action explanatory drawing which shows the flow state of the metal at the time of burring process. It is sectional explanatory drawing which shows the structure of the metal mold | die which concerns on 2nd Embodiment used for the burring processing method of this invention. It is explanatory drawing in the case of stamping the thin part which remained in the protrusion part. It is explanatory drawing which shows the deformation | transformation form of the pressurization protrusion part in a die metal mold | die. It is explanatory drawing which shows the deformation | transformation form of the pressurization protrusion part in a punch metal mold | die.

  Referring to FIG. 1, FIG. 1 shows a mold 1 used for a burring method in which a burring process is performed on a plate-like workpiece W without forming a pilot hole in advance. The mold 1 includes a punch mold 3 as a female mold and a die mold 5 as a male mold that are vertically opposed to each other. FIG. The state which formed the burring part (cylindrical protrusion part) BU on the upper surface of the workpiece | work W is shown.

  The punch die 3 is provided in a punch mounting hole provided in the punch holder 7 such as an upper turret in a turret punch press, for example, and can be moved up and down, and a plurality of lifter springs 9 provided in the punch holder 7 are provided. Supported to move up and down. More specifically, the punch mold 3 is provided with a cylindrical punch guide 11 fitted in the punch mounting hole so as to be movable up and down. A punch head 13 is vertically moved at the upper end of the punch guide 11. A punch driver 15 screwed so as to be adjustable in position is detachably and integrally fixed with a fixing tool such as a bolt.

  The punch guide 11 and the punch driver 15 can be configured as a single unit in advance. Therefore, the punch head 13 is integrally provided at the upper end portion of the punch guide 11 via the punch driver 15.

  A plate pressing member 17 is detachably and integrally attached to the lower end portion of the punch guide 11 via a fixture such as a bolt or a positioning pin. A burring portion molding concave portion 19 for forming a burring portion BU is formed on the upper surface of the work W at the center of the lower surface of the plate pressing member 17, and the burring portion molding concave portion 19 is a through-hole penetrating in the vertical direction. 21 is formed.

  In the punch guide 11, an elevating body 25 having a pressure projecting portion 23 is provided so as to be movable up and down and urged downward. More specifically, the punched cylinder spacer 27 and the punched cylinder 27 are arranged in the punch guide 11 so as to be movable up and down above the elevating body 25 and so as to come into contact with the lower surface of the punch driver 15. An elastic member 29 such as a coil spring or urethane rubber is elastically provided between the lower surface of the driver 15 and urges the elevating body 25 downward through the spacer 27.

  The rod-like pressure projecting portion 23 provided on the lower surface of the elevating body 25 so as to project downward is inserted into the through hole 21 of the plate pressing member 17 so as to be movable up and down. And the front end surface 23F of the said pressurization protrusion part 23 is the structure provided with the plane part of the direction orthogonal to the said burring part shaping | molding recessed part 19, ie, the axial center of the said through-hole 21. As shown in FIG.

  By the way, when the punch die 3 is lifted by the lifter spring 9, the lift body 25 is in contact with the upper surface of the plate pressing member 17, and the pressurization member provided on the lower surface of the lift body 25 is in contact with the upper surface of the lift body 25. The height position of the lower end surface (tip surface) of the pressure projecting portion 23 is substantially the same height as the lower surface of the plate pressing member 17 or is in a state of being immersed in a position above the lower surface.

  The die mold 5 is mounted in a die mounting hole provided in the die holder 31 such as a lower turret in a turret punch press. The die mold 5 includes a die main body 33 mounted in the die mounting hole, and a pressurization facing the pressurizing protrusion 23 in the punch mold 3 is provided at the center of the die main body 33. A protruding portion 35 is provided to protrude upward. The diameter of the pressure protrusion 35 is smaller than the diameter of the burring portion molding recess 19. And the front end surface (upper end surface) 35F of this pressurization protrusion part 35 protruded in the plane parallel to the lower end surface 23F of the said pressurization protrusion part 23 in the said punch metal mold | die 3, or the said burring part shaping | molding recessed part 19 inward direction. A convex curved surface is formed.

  An annular ejector plate 37 surrounding the pressure projecting portion 35 is provided on the upper surface of the die body 33 so as to be movable up and down and urged upward. More specifically, a coil, for example, is disposed between an elevating plate 41 provided in a vertically movable guide pin 39 provided on the lower surface of the die body 33 and a spring seat 43 provided at a lower end portion of the guide pin 39. An elastic member 45 such as a spring is mounted. A lower end portion of a pin 47 having an upper end portion attached to the ejector plate 37 through the die body 33 so as to move up and down is in contact with the upper surface of the elevating plate 41.

  Therefore, the ejector plate 37 is always urged upward by the elastic member 45 through the elevating plate 41 and the pin 47. In order to regulate the rise of the ejector plate 37, an upper end portion of a stopper bolt 49 penetrating the die main body 33 so as to move up and down is attached to the lower surface of the ejector plate 37. In the state where the ejector plate 37 is raised by the urging force of the elastic member 45 and the rise is restricted by the stopper bolt 49 (the state where the workpiece W is not subjected to burring), the ejector plate 37 The upper surface is located slightly higher than or equal to the upper end of the pressure protrusion 35.

  In the configuration as described above, when the position where the workpiece W should be subjected to burring is moved and positioned on the die 5, the workpiece W is urged upward by the elastic member 45 and the rise is restricted by the stopper bolt 49. The ejector plate 37 is in a state of being supported. In this state, when the punch head 13 of the punch mold 3 is struck by a striker (ram) ST provided in the punch press so as to be movable up and down and the punch mold 3 is lowered against the urging force of the lifter spring 9, The lower surface of the plate pressing member 17 provided in the punch die 3 comes into contact with the upper surface of the workpiece W.

  As described above, when the lower end surface of the plate pressing member 17 comes into contact with the workpiece W, the workpiece W is pinched by the plate pressing member 17 in the punch die 3 and the ejector plate 37 in the die die 5 and is punched. The pressure protrusion 23 in the mold 3 and the pressure protrusion 35 in the die mold 5 are sandwiched. Thereafter, when the striker ST is further lowered, the ejector plate 37 and the plate pressing member 17 are lowered in a state where the workpiece W is clamped against the urging force of the elastic member 45 in the die mold 5. Accordingly, the pressure protrusion 35 in the die mold 5 is relatively raised, and a part of the workpiece W is pressed and inserted into the burring molding recess 19.

  That is, in the work W, the portion sandwiched between the plate pressing member 17 in the punch die 3 and the ejector plate 37 in the die die 5 is the pressure protrusion 23 in the punch die 3 and the pressurizing portion in the die die 5. It will descend relative to the portion clamped by the pressure projection 35. In other words, in the work W, the portion sandwiched between the pressing protrusions 23 and 35 of the punch die 3 and the die die 5 is raised relative to the peripheral portion (FIG. 2). (See (A)).

  As described above, when the portion of the work W sandwiched between the pressurizing protrusion 23 in the punch mold 3 and the pressurizing protrusion 35 in the die mold 5 is relatively raised, the sandwiching of the work W is performed. As shown in FIG. 2A, the pressed portion is slightly protruded into the burring portion forming recess 19 in the plate pressing member 17. At this time, the metal around the clamped portion is pulled in the direction of the clamped portion and flows in the same direction as indicated by an arrow A in FIG.

  And if the upper part of the spacer 27 contact | abuts to the lower surface of the punch driver 15, the relative raise of the raising / lowering body 25 will be stopped. Thus, in a state where the relative lifting of the elevating body 25 is stopped, the front end surface (lower end surface) 23F of the pressurizing protrusion 23 is in a state of being raised from the lower surface of the plate pressing member 17. The burring portion forming recess 19 formed on the lower surface of the plate pressing member 17 is immersed.

  As described above, in the workpiece W, the portion sandwiched between the pressurizing protrusion 23 in the punch die 3 and the pressurizing protrusion 35 in the die die 5 is slightly inserted into the burring portion forming recess 19 of the plate pressing member 17. When the striker ST is further lowered, the portion of the work W sandwiched between the plate presser member 17 and the ejector plate 37 moves further downward. At the same time, the portion of the workpiece W sandwiched between the upper and lower pressurizing protrusions 23 and 35 is strongly pressed so that the thickness is reduced. Therefore, the portion of the metal clamped by the upper and lower pressurizing protrusions 23 and 35 is strongly clamped and pressurized to flow radially outward as indicated by an arrow B in FIG. Will be.

  At this time, the lower end surface 23F of the pressurizing protrusion 23 in the punch mold 3 is formed into a flat surface, and the upper end surface of the pressurizing protrusion 35 in the die mold 5 is formed into a convex curved surface. As a result, the metal in the clamped portion extends radially outward along the lower end surface (tip surface) 23F of the pressurizing protrusion 23 in the punch die 3, as indicated by an arrow B in FIG. Effectively directed and fluidized.

  Thereafter, when the ejector plate 37 in the die mold 5 comes into contact with the die main body 33 and stops descending (see FIG. 2C), the portion of the work W sandwiched between the plate pressing member 17 and the ejector plate 37 is also pressed. It is more powerfully pressed and pressed. Accordingly, a part of the metal of the work W pressed and pressed by the plate pressing member 17 and the ejector plate 37 is flowed radially inward (arrow A), and the upper and lower pressurizing protrusions 23 and 35 are moved. It joins with the metal that flows in the radial outward direction and flows in the upward direction of the burring portion forming recess 19.

  When the burring portion forming recess 19 is filled with metal, a cylindrical burring portion BU protruding upward is formed on the upper surface of the workpiece W. At this time, the outer surface of the burring portion BU is in a state where the inner peripheral surface of the burring portion molding recess 19 is transferred, and is a smooth surface. Then, the thin portion WA that is crushed by the upper and lower pressure protrusions 23 and 35 remains inside the upper end portion of the burring portion BU (see FIG. 2D).

  As described above, when the burring portion BU is formed, the cylindrical portion of the burring portion BU is formed thinner than the workpiece W, and can be formed with a larger protruding dimension. The thin portion WA is formed to be extremely thinner than the cylindrical portion of the burring portion BU.

  As described above, after burring the workpiece W, the striker ST is returned to its original raised position, the workpiece W is removed from between the punch die 3 and the die die 5, and the punch die 3, die A burring portion BU having a desired shape is formed on the upper surface of the workpiece W by punching the thin portion with a punch and die for punching that is separate from the die 5 (FIG. 2 (E)). reference).

  As can be understood from the above description, as the mold for forming the burring portion BU on the upper surface of the work W, the mold 1 provided with the punch mold 3 and the die mold 5 described above was formed. Two types of molds, ie, a punch for punching a thin portion in the burring unit BU and a mold having a die, may be used, and the number of molds is reduced. Moreover, according to the said structure, the hole of burring part BU can be made into the same diameter from the lower surface of the workpiece | work W to the front-end | tip (upper end) of burring part BU, and the effective length of the hole for forming a screw thread is made more Can be long. Therefore, many threads can be formed in the burring portion BU, and the conventional problems as described above can be solved.

  By the way, although the said description demonstrated the case where the burring part BU was formed in the upper surface of the workpiece | work W, it is also possible to form the burring part BU in the lower surface of the workpiece | work W. FIG. Then, next, the metal mold | die for forming the burring part BU in the lower surface of the workpiece | work W is demonstrated.

  Referring to FIG. 3, a mold 51 for forming a burring portion BU on the lower surface of a workpiece W includes a punch mold 53 as a male mold and a die mold 55 as a female mold.

  The punch die 53 includes a cylindrical punch guide 57 that is supported by a punch holder (not shown in FIG. 3) in a punch press so as to be movable up and down. A plate pressing portion 57A for pressing the workpiece W is provided at the lower portion of the punch guide 57. A punch driver 63 penetrating through a retainer collar 61 provided on the upper portion of the punch guide 57 is integrally provided on an upper portion of the punch body 59 provided in the punch guide 57 so as to be movable up and down. A powerful stripper spring 67 such as a disc spring is mounted between the punch head 65 screwed to the upper end portion of the punch driver 63 and the retainer collar 61. A pressing protrusion 69 that penetrates the plate pressing portion 57A and can protrude downward is integrally provided at a lower portion of the punch body 59. The pressure protrusion 69 corresponds to the pressure protrusion 35 in the die mold 5.

  The die mold 55 includes a die base 71, and the die base 71 includes a cylindrical die body 75 including a burring molding recess (through hole) 73 corresponding to the burring molding recess 19 in the punch mold 3. Are integrally attached. In the die main body 75, an elevating body 77 corresponding to the elevating body 25 in the punch die 3 is provided so as to be movable up and down and in contact with the die base 71. The lifting body 77 is provided with a pressure protrusion 79 corresponding to the pressure protrusion 23. The elevating body 77 is urged upward by an elastic member 81 corresponding to the elastic member 29.

  In the above configuration, after the workpiece W is positioned on the die mold 55, the punch head 65 is struck by a striker (not shown in FIG. 3) provided in the punch press, and the punch mold 53 is lowered. Similar to the operation of the mold 1, a part of the workpiece W is pressed and inserted into the burring molding recess 73 by the pressure protrusion 69. And the part pinched by the up-and-down pressurization protrusion parts 69 and 79 in the workpiece | work W is crushed, and the burring part BU is formed in the lower surface of the workpiece | work W. FIG.

  By the way, as described above, when the burring portion BU is projected and formed on the workpiece W, as described above, the thin portion WA remains at the tip of the burring portion BU. Since the thin portion WA is strongly crushed by the upper and lower pressure protrusions 23 and 35, the thin portion WA is formed to be extremely thin as compared with the cylindrical portion of the burring portion BU. Therefore, the process of punching out the thin part WA involves shaving the inner peripheral surface of the burring part BU. Therefore, the inner peripheral surface of the burring portion BU to be tapped can be finished with high accuracy.

  In addition, when the thin portion WA in the burring portion BU is punched (shaved), it can be performed with a light load. Therefore, as a die, the punching die 85 in the shaving die 83 is used to place the burring portion BU of the workpiece W as a die die as shown in FIGS. 4 (A), 4 (B) or 4 (C), 4 (D). The punch blade part is held in a state of being directly sandwiched between the mold 87, a state in which the peripheral part (near the periphery) of the burring part BU is sandwiched, or a state in which the peripheral part of the burring part BU is pressed against the die mold 87. The shaving process can be performed by descending 85B.

  By the way, the present invention is not limited to the embodiment as described above, but can be implemented in various forms. That is, as the form of the pressurizing protrusion 35 in the die mold (male) 5, for example, the form shown in FIGS. 5 (A), (B), and (C) can be adopted, and the pressurization can be performed. The tip surface of the protrusion 35 can be conical as shown in FIG. 6D, or can be spherical as shown in FIG. 6D. is there. Further, as shown in (c) of FIG. 6D, it is possible to chamfer the peripheral edge to the C surface or the R surface to form the end surface into a flat surface. In this case, it becomes a convex curved surface by including a chamfered portion.

  Moreover, as a form of the pressurization protrusion part 69 in the said punch metal mold | die 53, it is also possible to set it as a form as shown to FIG. 6 (A), (B). And the front end surface of the pressurizing protrusion 69 is similar to (a), (b), (c) of FIG. 5 (D), (a), (b), (c) of FIG. 6 (C). As shown in Fig. 5, it is possible to form a cone shape, a spherical shape, or a shape including a chamfered portion on the periphery.

1 Die 3 Punch Die (Female)
5 Die mold (male mold)
17 Plate holding member 19 Burring molding recess 21 Through hole 23, 35 Pressurized protrusion 23F, 35F End face 25 Lifting body 29 Elastic member 33 Die body 51 Mold 53 Punch mold (male)
55 Die mold (female)
59 Punch body 69 Pressurized protrusion 73 Burring molding recess 75 Die body 79 Pressurized protrusion 83 Shaving mold

Claims (1)

A method of performing burring processing on a plate-like workpiece, wherein a part of the workpiece is pressed and inserted into a burring portion molding recess provided in a female die by a pressure projection provided in the male die. The pressure protrusion is inserted into the burring portion forming recess, and is provided in a lifting body that is movable up and down on the tip surface of the pressure protrusion and the bottom of the burring portion forming recess or the female mold. The tip of the projection is crushed between the tip of the projection to form a thin portion at the tip of the projection that is thinner than the cylindrical portion of the projection, and the thin portion of the tip is punched out A burring method comprising: shaving the inner peripheral surface of the protrusion when processing.

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