JP2010260078A - Burring method and burring die - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a burring method and a burring die for forming a burring part by which the more number of screw threads are formed by reducing the number of dies to be used and making the effective length of a hole for forming the screw threads longer. <P>SOLUTION: The burring method includes: an stage (a) where a planar workpiece W is held with a punching die and a dieing die, formed into thin thickness by sandwiching and pressurizing a portion where is sandwiched by a pressurizing projecting part 23 provided on the punching die and a pressurizing projecting part 35 provided on the dieing die opposing to the pressurizing/projecting part, and also by making the metal in the portion where is sandwiched and pressurized flow into an annular recessed part 19 where is formed around the pressurizing/projecting part provided on the punching die or the dieing die, a cylindrical projecting part BU is formed on one side face of the upper surface or the under surface of the workpiece W and also a recessed part is formed on the other side face of the workpiece W; and a stage (b) where the portion where is made into the thin thickness by the pressurizing projecting parts of the punching die and the dieing die is punched. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method and a mold for performing a burring process on a plate-shaped workpiece, and more particularly to a method for performing a burring process without forming a pilot hole in advance in a workpiece and a mold used for the method.

  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.

  The present invention has been made in view of the conventional problems as described above, and is a burring method for performing burring on a plate-shaped workpiece without forming a pilot hole in advance, and includes a punch die and a die die. A plate-shaped workpiece is sandwiched, and the portion sandwiched between the pressure protrusion provided in the punch mold and the pressure protrusion provided in the die mold is opposed to the pressure protrusion and pressed. And forming a thin wall and flowing the metal to be pressed and pressed into an annular recess formed around the pressurizing protrusion provided in the punch mold or die mold, Forming a cylindrical protrusion on one side of the upper or lower surface of the workpiece and forming a recess on the other side of the workpiece (a), and sandwiching between the pressing protrusions of the punch mold and the die mold (B) Step of punching out the thinned part by pressing , And it is characterized in that it comprises a.

  In addition, the die used in the step (a) in the burring method includes a punch die and a die die, and the punch die has a cylindrical punch guide provided with a punch head at an upper end portion. An elevating body having a pressure projecting portion at a lower end portion thereof is vertically movable and urged downward, and a plate pressing member having a through hole through which the pressure projecting portion vertically penetrates is provided in the punch. Provided at the lower end of the guide and provided on the lower surface of the plate pressing member with an annular recess surrounding the pressurizing protrusion, and the die mold is the pressurizing protrusion in the punch mold The die body is provided with a pressure projecting portion opposite to the die, and an ejector plate is provided around the pressure projecting portion so as to be vertically movable and urged upward.

  Further, in the mold, the tip surface of the pressure protrusion in the punch mold is formed into a convex curved surface, and the tip surface of the pressure protrusion in the die mold is the convex shape. A concave curved surface corresponding to the curved surface is formed.

  The die used in the step (a) in the burring method includes a punch die and a die die, and the punch die is formed in a cylindrical punch guide and has a punch head at an upper end portion. A punch body having a pressurizing protrusion that can be protruded downward from the punch guide, and is provided with a punch body that can be moved up and down and urged upward, and the die mold is provided in a die body. Further, an ejector plate is provided around the upper protrusion so as to be vertically movable and urged upward, and provided on the upper surface of the upper protrusion so as to face the pressure protrusion in the punch mold. An annular recess is provided around the pressure protrusion.

  Further, in the mold, the upper surface of the pressure protrusion in the die mold is formed at the same height as the upper surface of the upward protrusion or lower than the upper surface of the upward protrusion. It is characterized by.

  According to the present invention, the number of processing steps is small, the number of molds to be used is reduced, and the molding height of the burring portion can be increased. Further, burrs are not generated at the end of the burring portion, the effective length of the hole in the burring portion can be increased, and more threads can be processed during screw processing.

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.

  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 and a die mold 5 which are vertically opposed to each other. FIG. 1 illustrates a burring portion (on the upper surface of the workpiece W by the punch mold 3 and the die mold 5). The state which shape | molded the cylindrical protrusion part BU 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 forming recess 19 for forming a burring portion BU is formed on the upper surface of the work W at the center portion of the lower surface of the plate pressing member 17, and the center portion of the burring portion forming recess 19 is formed in the vertical direction. A penetrating through hole 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-shaped pressure projecting portion 23 provided on the lower surface of the lifting body 25 so as to project downward passes through the through hole 21 of the plate pressing member 17, and the lower end portion of the pressure projecting portion 23. Protrudes into the burring portion molding recess 19. Therefore, an annular recess is formed between the outer peripheral surface of the pressure protrusion 23 and the inner peripheral surface of the burring portion molding recess 19. In other words, it has a configuration including an annular recess surrounding the pressurizing protrusion 23.

  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. The height position of the lower end surface (tip surface) of the pressure protrusion 23 is substantially equal to the lower surface of the plate pressing member 17 or the height position slightly protruding downward from the lower surface of the plate pressing member 17. It is provided. And the lower end surface of the said pressurization protrusion part 23 is formed in the convex curved surface like hemisphere, for example.

  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 front end surface (upper end surface) of the pressing protrusion 35 is formed as a concave curved surface corresponding to the convex curved surface of the lower end surface of the pressing protrusion 23 in the punch mold 3.

  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 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 die 3 is struck by a striker (ram) ST provided in the punch press so as to be movable up and down and the punch die 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 and the lower end surface (tip surface) of the pressing protrusion 23 are in contact with the upper surface of the workpiece W.

  As described above, when the lower end surfaces of the plate pressing member 17 and the pressure protrusion 23 come into contact with the workpiece W, the workpiece W is sandwiched between the plate pressing member 17 in the punch die 3 and the ejector plate 37 in the die die 5. In addition to being pressed, the pressure protrusion 23 in the punch die 3 and the pressure protrusion 35 in the die die 5 are sandwiched. Thereafter, when the striker ST is further lowered, the punch guide 11 is lowered against the urging force of the elastic member 29 because the pressing protrusion 23 in the punch die 3 is in contact with the workpiece W. .

  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) of the pressurizing protrusion 23 is in a state of being raised from the lower surface of the plate pressing member 17; It is in a state of protruding into a burring portion forming recess 19 formed on the lower surface of the plate pressing member 17.

  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 outward in the radial direction as indicated by an arrow B in FIG. Will be.

  At this time, the lower end surface of the pressing protrusion 23 in the punch die 3 is formed into a convex curved surface, and the upper end surface of the pressing protrusion 35 in the die die 5 corresponds to the convex curved surface. Due to the formation of the concave curved surface, the metal of the sandwiched portion is around the pressurizing protrusion 23 in the punch die 3 as shown by an arrow B in FIG. The burring portion forming concave portion 19 is effectively directed to flow upward.

  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. And the thin part which was crushed by the said upper and lower pressure protrusion parts 23 and 35 remains inside the said burring part BU (refer FIG.2 (D)). Under the present circumstances, the recessed part of the same diameter formed by the upper and lower pressurization protrusion parts 23 and 35 is formed in the upper and lower sides of the said thin part.

  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 and a die mold 55.

  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 die mold 55 includes a die body 71, and a large-diameter upward protruding portion 73 is provided at the center of the upper surface of the die body 71. An ejector plate 75 is provided around the upward protrusion 73 so as to be movable up and down. The ejector plate 75 is urged upward by an elastic member 77 elastically mounted between the ejector plate 75 and the die main body 71, and the upward position is a stopper attached to the lower surface of the ejector plate 75. It is regulated by a bolt 79.

  A pressing protrusion 81 facing the pressing protrusion 69 is formed at the center of the upper surface of the upward protrusion 73. The upper surface of the pressure protrusion 81 is formed slightly lower than the upper surface of the upward protrusion 73, and an annular recess 83 as a burring portion forming recess is formed around the pressure protrusion 81. It is formed.

  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, the portion of the work W sandwiched between the upper and lower pressure protrusions 69 and 81 is crushed, and the metal in this portion flows into the burring portion forming recess 83, so that the work W A burring portion BU is formed on the lower surface of the.

DESCRIPTION OF SYMBOLS 1,51 Die 3,53 Punch die 5,55 Die die 17 Plate pressing member 19 Burring part shaping | molding recessed part 23,35,69,81 Pressurization protrusion part 25 Elevator 29 Elastic member 33,71 Die body 37, 75 Ejector plate 59 Punch body 73 Upward projecting part 83 Concave part (burring part forming concave part)

Claims (5)

A burring method for performing burring on a plate-shaped workpiece without forming a pilot hole in advance,
(A) A plate-like workpiece is sandwiched between a punch die and a die die, a pressure protrusion provided in the punch die, and a pressure protrusion provided in the die mold so as to face the pressure protrusion. The portion clamped and pressed is formed into a thin wall by pressing and pressing, and the metal of the portion to be pressed and pressed is formed around the pressurizing protrusion provided in the punch mold or die mold. Flowing into the annular recess that is formed, forming a cylindrical protrusion on one side of the upper or lower surface of the workpiece and forming a recess on the other side of the workpiece;
(B) a step of punching out a thinned portion that has been pressed and pressed by the pressing protrusions of the punch die and the die die;
A burring method characterized by comprising:   It is a metal mold | die used for the said (a) process in the burring processing method of Claim 1, Comprising: A punch metal mold | die and a die metal mold | die, The said punch metal mold | die was equipped with the punch head in the upper end part. In the punch guide, a plate holding member provided with an elevating body having a pressure projecting portion at the lower end portion and capable of vertically moving and urging downward, and having a through-hole through which the pressure projecting portion vertically penetrated. At the lower end of the punch guide, and an annular recess that surrounds the pressing protrusion on the lower surface of the plate pressing member. A die characterized in that a pressurizing protrusion facing the pressure protrusion is provided in the die body, and an ejector plate is provided around the pressure protrusion so as to be vertically movable and urged upward.   3. The mold according to claim 2, wherein a front end surface of the pressurizing protrusion in the punch mold is formed into a convex curved surface, and a front end surface of the pressurizing protrusion in the die mold is A mold having a concave curved surface corresponding to a convex curved surface.   A die used in the step (a) in the burring method according to claim 1, comprising a punch die and a die die, and the punch die is provided at an upper end portion in a cylindrical punch guide. A punch body having a pressing projection that can be protruded downward from the punch guide, and is provided with a punch body that can be moved up and down and urged upward. An ejector plate is provided around the upper protruding portion of the main body so as to be movable up and down and biased upward, and on the upper surface of the upper protruding portion, the pressure protruding portion of the punch mold is opposed to the pressing protruding portion. A mold having an annular recess around the pressure protrusion provided.   5. The mold according to claim 4, wherein an upper surface of the pressure protrusion in the die mold is formed at the same height as the upper surface of the upward protrusion or lower than the upper surface of the upward protrusion. A mold characterized by that.

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