JP2012196707A - Method of molding workpiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of molding a workpiece capable of accurately molding the workpiece.SOLUTION: The method of molding the workpiece is used for molding the workpiece 2 including a flange 60 and a tubular part 4 rising from its inner peripheral part. The method includes an overhang molding process of molding a projecting surface-like overhang part 46 at a predetermined part of the plate-like workpiece 2, and a compression molding process of molding the tubular part 4 on the overhang part 46 by compressing the workpiece 2, and molding the flange 60 in an outer peripheral part of the workpiece 2. In the compression molding process, an excess thickness part 62 projecting toward a direction opposite to the tubular part 4 is formed at least at a part of an inner edge of the flange 60.

Description

  The present invention relates to a workpiece forming method for forming a workpiece into a predetermined shape by performing drawing or the like on a workpiece composed of a metal plate.

  Various forming methods for forming a workpiece into a predetermined shape by subjecting the workpiece (blank material) made of a metal plate to drawing or the like have been proposed. For example, when molding a workpiece having a flange portion and a cylindrical portion rising from the inner peripheral edge portion, the following first molding method or second molding method is performed.

  In the first molding method, a stretch molding process, a compression molding process, and a drawing process are performed in this order using a press die (see, for example, Patent Document 1). First, as shown in FIG. 15A, an overhang forming process for overhang forming the plate-like workpiece 100 is performed, and a convex overhang portion 102 is formed at a predetermined portion of the plate-like workpiece 100. Next, as shown in FIG. 15 (b), a compression molding process for compressing the workpiece 100 is performed to form a cylindrical portion 104 on the overhang portion 102 and a flange portion on the outer peripheral portion of the workpiece 100. 106 is formed. Thereafter, as shown in FIG. 15C, a drawing process for drawing the workpiece 100 is performed to form the cylindrical portion 104 into a predetermined shape.

  In the second forming method, the sintering process and the grinding process are performed in this order (see, for example, Patent Document 2). First, a sintering process is performed in which the green compact is heated and sintered, and a workpiece (sintered body) having a flange portion and a cylindrical portion rising from the inner peripheral edge portion is formed. Next, a grinding process for grinding the cylindrical portion of the workpiece is performed, and the cylindrical portion is formed into a predetermined shape (for example, an irregular shape). In this grinding step, for example, a thin portion with a small thickness is formed on the distal end side of the tubular portion by making the grinding amount on the distal end side of the tubular portion larger than the grinding amount on the proximal end side of the tubular portion. At the same time, a thick part having a large thickness is formed on the base end side of the cylindrical part.

JP 2002-336914 A JP 2009-62614 A

  The conventional method for forming a workpiece as described above has the following problems. In the first molding method, when the workpiece 100 is compressed in the compression molding step, a part of the material constituting the cylindrical portion 104 is caused to flow toward the inner peripheral edge portion 108 of the flange portion 106, whereby the flange portion 106. The inner peripheral edge portion 108 is formed into a shape close to an edge shape (R shape) (see FIG. 15B). However, in order to form in this way, the force acting on the cylindrical portion 104 must be increased by the press mold, and therefore, the base end portion of the cylindrical portion 104 may be buckled. In such a portion where buckling has occurred, the inner surface of the proximal end portion of the cylindrical portion 104 is wavy and the smoothness is lowered.

  Further, by squeezing the cylindrical portion 104 in the drawing process, a part of the material constituting the cylindrical portion 104 is directed toward the inner peripheral edge portion 108 of the flange portion 106 as indicated by an arrow in FIG. The inner peripheral edge 108 of the flange portion 106 is formed into an edge shape. Thus, in order to shape the inner peripheral edge 108 of the flange portion 106 into an edge shape, it is necessary to make the amount of drawing of the cylindrical portion 104 relatively large. However, when the amount of drawing is increased in this way, the force acting on the tubular portion 104 by the press die increases, and thus the base end portion 110 of the tubular portion 104 may be further buckled as described above. (See FIG. 15 (d)). Therefore, the first forming method has a problem that the workpiece 100 cannot be formed with high accuracy.

  Further, in the second forming method, when the cylindrical portion is ground in the grinding step, there is a limit in processing accuracy to reduce the thickness of the thin portion. For example, the thickness of the thin portion is about 0.00 mm. It is difficult to mold to 9 mm or less. For this reason, there is a problem in that the shape and dimensions of the workpiece as the final molded product are restricted, and the degree of freedom in molding the workpiece is reduced.

  An object of the present invention is to provide a workpiece forming method capable of forming a workpiece with high accuracy.

  Another object of the present invention is to provide a method for forming a workpiece that can increase the degree of freedom in forming.

The workpiece molding method according to claim 1 of the present invention is a workpiece molding method for molding a workpiece having a flange portion and a cylindrical portion rising from an inner peripheral edge thereof.
An overhang forming step of forming a convex overhang portion on a predetermined portion of a work made of a metal plate, and forming the cylindrical portion in the overhang portion by compressing the work, and forming an outer periphery of the work A compression molding step of molding the flange portion,
In the compression molding step, a surplus portion that protrudes in a direction opposite to the cylindrical portion is formed on an inner edge portion of the flange portion.

  The workpiece forming method according to claim 2 of the present invention is characterized in that, in the compression molding step, the surplus portion is formed over the entire circumference of the inner peripheral edge of the flange portion.

  In the workpiece molding method according to claim 3 of the present invention, a flattening molding step is performed after the compression molding step, and in the flattening molding step, the surplus portion is crushed to form the flange. The inner peripheral edge of the part is shaped flat.

According to a fourth aspect of the present invention, in the compression molding step, a punch, a blank holder mounted on the punch so as to be movable in the vertical direction, and a blank holder are arranged opposite to the blank holder. A surplus portion forming recess for forming the surplus portion is provided between the blank holder and the punch, and an outer peripheral portion of the surplus portion forming recess. Is formed in a taper shape or a round shape gradually reducing the diameter toward the radially inner side of the blank holder,
When compressing the workpiece, the outer peripheral portion of the workpiece is pressed and held between the die and the blank holder, and the punch is pushed into the overhanging portion of the workpiece, whereby the overhanging portion is When the cylindrical part is molded, the flange part is molded on the outer peripheral part of the work, and the material constituting the work flows into the surplus part forming concave part, whereby the inner peripheral part of the flange part is A surplus portion is formed.

  Further, in the work molding method according to claim 5 of the present invention, in the compression molding step, when the surplus part is formed in the surplus part forming recess, an inner peripheral part of the surplus part is formed. A gap exists between the punches.

  Moreover, when the workpiece | work shaping | molding method of Claim 6 of this invention compresses the said workpiece | work by restraining at least one part of the outer-periphery edge part of the said flange part by a stopper member in the said compression molding process. The outer peripheral edge portion of the flange portion is prevented from expanding radially outward.

Further, the workpiece molding method according to claim 7 of the present invention is a workpiece molding method for molding a workpiece having a flange portion and a cylindrical portion rising from an inner peripheral edge portion thereof,
An overhang forming step of forming a convex overhang portion on a predetermined portion of a work made of a metal plate, and forming the cylindrical portion in the overhang portion by compressing the work, and forming an outer periphery of the work A compression molding step for molding the flange portion, and a drawing or ironing step for molding the tubular portion into a predetermined shape by squeezing or squeezing the workpiece,
In the drawing process or the ironing process, part of the material constituting the distal end side of the cylindrical part flows to the proximal end side of the cylindrical part by squeezing or squeezing the distal end side of the cylindrical part. And the thickness of the tubular portion on the proximal end side is increased to form a thick portion on the proximal end side of the tubular portion, and the thickness on the distal end side of the tubular portion is decreased to reduce the thickness of the tubular portion. A thin-walled portion is formed on the distal end side of the cylindrical portion.

  According to the workpiece forming method of the first aspect of the present invention, in the compression molding step, the surplus portion that protrudes in the direction opposite to the cylindrical portion is formed on the inner edge portion of the flange portion. Thereby, when compressing a workpiece | work, a part of material which comprises a cylindrical part flows toward the inner edge part of a flange part, and this fluidized material comes to escape as a surplus part. When the surplus portion is formed in this way, the force acting on the cylindrical portion by the press die is reduced compared to the case where the inner peripheral edge portion of the flange portion is formed in a shape close to an edge shape as in the prior art. It is possible to suppress buckling of the cylindrical portion. In addition, by forming a surplus part at the inner edge of the flange part in the compression molding process, for example, in the drawing process after the compression molding process, a part of the material constituting the cylindrical part is transferred to the inner edge of the flange part. The amount of fluid flowing toward the part can be suppressed, and the amount of squeezing of the cylindrical part can be reduced. Therefore, the force acting on the cylindrical portion by the press die can be reduced, and the occurrence of buckling in the cylindrical portion can be suppressed. Therefore, the workpiece can be formed with high accuracy. In the present specification, the “inner peripheral edge” of the flange portion is a range over the entire circumference of the opening edge of the flange portion, and the “inner edge” of the flange portion refers to the opening edge of the flange portion. Part of the range, i.e. part of the inner periphery.

  Further, according to the method for molding a workpiece according to claim 2 of the present invention, in the compression molding process, the surplus portion is formed over the entire circumference of the inner peripheral edge of the flange portion, so that the cylindrical portion is configured. The amount by which a part of the material flows toward the inner peripheral edge of the flange portion can be suppressed more effectively, and the amount of squeezing of the cylindrical portion can be suppressed more effectively.

  Further, according to the method for molding a workpiece according to claim 3 of the present invention, in the flattening molding step performed after the compression molding step, the surplus portion is crushed and the inner peripheral edge of the flange portion is molded flat. Therefore, the inner peripheral edge of the flange portion can be formed into an edge shape. Moreover, the material which comprises the surplus part comes to flow to the internal peripheral surface of a cylindrical part, and the smoothness in the internal peripheral surface of a cylindrical part can be improved. Thereby, the internal peripheral surface of a cylindrical part can be shape | molded in the surface roughness equivalent to a grinding process.

  Further, according to the method for molding a workpiece according to claim 4 of the present invention, a surplus part forming recess for forming a surplus part is provided between the blank holder and the punch. Since the outer peripheral portion of the forming concave portion is formed in a taper shape or a round shape that gradually decreases in diameter toward the inside in the radial direction of the blank holder, the outer peripheral portion of the surplus portion is the outer periphery of the concave portion for forming the surplus portion. Corresponding to the shape of the portion, it is formed in a taper shape or a round shape that gradually decreases in diameter toward the inside in the radial direction of the flange portion. Thereby, when compressing a workpiece | work, the material which comprises a workpiece | work becomes easy to flow into the recessed part for surplus part formation, and a surplus part can be formed smoothly.

  Further, according to the method for molding a workpiece according to claim 5 of the present invention, when the surplus portion is formed in the surplus portion forming recess in the compression molding step, the inner peripheral portion of the surplus portion and the punch There is a gap between them. By forming the surplus portion so that there is a gap in this way, the force acting on the workpiece by the press die can be reduced, and the occurrence of buckling in the cylindrical portion can be more effectively suppressed. Can do.

  According to the workpiece molding method of the present invention, at least a part of the outer peripheral edge of the flange portion is restrained by the stopper member in the compression molding step. Therefore, when the workpiece is compressed, the flange portion It is prevented that the outer peripheral edge part expands radially outward. Thereby, in the compression molding process, the material constituting the cylindrical portion is restrained from flowing toward the outer peripheral edge portion of the flange portion, so that the material constituting the cylindrical portion is changed to the inner edge portion (or inner peripheral edge of the flange portion). Part) can be made to flow efficiently, and the surplus part can be formed efficiently.

  Further, according to the method for forming a workpiece according to claim 7 of the present invention, the tip side of the cylindrical part is configured by squeezing or squeezing the tip side of the cylindrical part in the drawing or ironing process. Part of the material flows to the base end side of the cylindrical portion. As a result, the thickness on the proximal end side of the tubular portion is increased and the thick portion is formed on the proximal end side of the tubular portion, and the thickness on the distal end side of the tubular portion is decreased and the tubular portion is reduced. A thin-walled portion is formed on the tip side. By such press forming (cold press forming), the thickness of the thin portion is further reduced (for example, 0.9 to 1.1 mm) as compared with the conventional forming method by the sintering process and the grinding process described above. Degree) can be molded. Accordingly, the thickness of the cylindrical portion can be freely controlled, and the degree of freedom in forming the workpiece can be increased.

It is a perspective view which shows the workpiece | work shape | molded by the shaping | molding method of the workpiece | work by one Embodiment of this invention. It is sectional drawing which shows the state before shape | molding a workpiece | work in an overhang | projection shaping | molding process. It is sectional drawing which shows the state after shape | molding a workpiece | work in an overhang | projection shaping | molding process. It is sectional drawing which shows the state before shape | molding a workpiece | work in a compression molding process. It is sectional drawing which shows the state after shape | molding a workpiece | work in a compression molding process. It is an expanded sectional view of the workpiece | work in FIG. It is sectional drawing of the workpiece | work and stopper member by the AA line in FIG. It is a perspective view which shows the workpiece by which compression molding was carried out. It is sectional drawing which shows the state before shape | molding a workpiece | work in a drawing process. It is sectional drawing which shows the state after shape | molding a workpiece | work in a drawing process. It is an expanded sectional view of the workpiece | work in FIG. It is sectional drawing which shows the state before shape | molding a workpiece | work in a 1st stamping shaping | molding process. It is sectional drawing which shows the state after shape | molding a workpiece | work in a 1st stamping shaping | molding process. It is sectional drawing which shows the modification of the recessed part for surplus part formation. It is a figure for demonstrating the shaping | molding method of the conventional workpiece | work.

  Hereinafter, an embodiment of a method for forming a workpiece according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view showing a work formed by a work forming method according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a state before the work is formed in an overhang forming process. 3 is a cross-sectional view showing a state after the work is formed in the overhang forming process, FIG. 4 is a cross-sectional view showing a state before the work is formed in the compression forming process, and FIG. 5 is a compression forming process. 6 is a cross-sectional view showing a state after forming the work in FIG. 6, FIG. 6 is an enlarged cross-sectional view of the work in FIG. 5, and FIG. 7 is a cross-sectional view of the work and the stopper member along the line AA in FIG. 8 is a perspective view showing the compression-molded work, FIG. 9 is a cross-sectional view showing a state before the work is formed in the drawing process, and FIG. 10 is a work in the drawing process. Molded 11 is an enlarged cross-sectional view of the work in FIG. 10, and FIG. 12 is a cross-sectional view showing a state before forming the work in the first punching forming process. These are sectional drawings which show the state after shape | molding a workpiece | work in a 1st stamping shaping | molding process.

  With reference to FIG. 1, a work 2 as a final molded product formed by the work forming method of the present embodiment has a substantially cylindrical tubular portion 4. A pair of recesses 6 are formed on the outer peripheral surface of the cylindrical portion 4, and the pair of recesses 6 are disposed at substantially symmetrical positions with the central axis of the cylindrical portion 4 in between. Each concave portion 6 extends from the tip of the cylindrical portion 4 to the central portion in the length direction. A thin-walled portion 7 having a small thickness is formed on the distal end side of the cylindrical portion 4, and a thick-walled portion 8 having a large thickness is formed on the base end portion thereof. The thick part 8 protrudes somewhat in a ring shape radially outward. As described above, in this embodiment, the workpiece 2 is formed in a deformed shape in which the two-sided width is formed in the cylindrical portion 4 and the thickness of the cylindrical portion 4 varies depending on the part. The material of the workpiece 2 is formed of a metal material such as an SPCD material.

  2 to 12, the workpiece 2 described above is formed by the following forming method. In the workpiece forming method of the present embodiment, an overhang forming step, a compression forming step, a draw forming step (including a flattening forming step), a first punch forming step, and a second punch forming step are performed in this order.

  First, as shown in FIGS. 2 and 3, an overhang forming process is performed. The press die 10a used in the overhang forming step includes a lower die 12a and an upper die 14a disposed to face the upper side of the lower die 12a.

  The lower mold 12a includes a lower mold main body 16a, a punch holder 18a provided at an upper end portion of the lower mold main body 16a, and a punch 20a supported by the punch holder 18a. The punch 20a extends from the punch holder 18a toward the upper die 14a, and the tip thereof is configured to be substantially spherical. Further, a blank holder 22a is disposed facing the upper side of the punch holder 18a. An opening 24a is provided at the center of the blank holder 22a, and the tip of the punch 20a is movably inserted into the opening 24a. As a result, the blank holder 22a is attached to the tip of the punch 20a so as to be movable in the vertical direction. A cushion pin 26a is supported on the lower die body 16a and the punch holder 18a so as to be movable in the vertical direction, and a blank holder 22a is supported on an upper end portion of the cushion pin 26a. A predetermined pressure is applied to the cushion pin 26a toward the upper mold 14a by air pressure, hydraulic pressure, or the like. The lower die body 16a and the punch holder 18a are provided with a coil spring accommodating recess 28a, and a coil spring 30a is accommodated in the coil spring accommodating recess 28a. The upper end portion of the coil spring 30a is supported on the lower surface of the blank holder 22a, and the blank holder 22a is elastically biased toward the upper mold 14a by the coil spring 30a.

  The upper die 14a has an upper die main body 32a, a die holder 34a provided at the lower end of the upper die main body 32a, and a die 36a supported by the die holder 34a. A knockout accommodating space 38a is provided inside the upper mold main body 32a, and a knockout 40a is accommodated in the knockout accommodating space 38a so as to be movable in the vertical direction. A coil spring 42a is accommodated in the knockout accommodating space 38a, and the knockout 40a is elastically biased toward the lower mold 12a by the coil spring 42a. The die 36a is disposed to face the blank holder 22a. An opening 44a is provided at the center of the die 36a, and the lower end of the knockout 40a is movably inserted through the opening 44a. The shape of the opening 44a of the die 36a is configured in a round shape in which the inner diameter gradually increases outward in the radial direction. The upper die body 32a is drivingly connected to an elevating mechanism (not shown), and the elevating mechanism causes the upper die 14a to be lowered in a direction close to the lower die 12a or raised in a direction away from the lower die. .

  The overhang forming of the workpiece 2 using the press die 10a described above is performed as follows. As shown in FIG. 2, the workpiece 2 (blank material) composed of a metal plate is placed on the upper surface of the blank holder 22a, and the outer periphery thereof is held between the die 36a and the blank holder 22a. The thickness of the workpiece 2 is, for example, about 2.6 mm. When the upper die 14a is lowered in the direction approaching the lower die 12a in this state, as shown in FIG. 3, the blank holder 22a is pushed down against the elastic biasing force of the coil spring 30a by the die 36a, and the punch 20a is blanked. The workpiece 22 is pushed from below through the opening 24a of the holder 22a. When the punch 20a is pushed in this way, the central portion of the work 2 is plastically deformed into a convex shape along the tip portion of the punch 20a, and the outer peripheral portion thereof is curved along the inner peripheral surface of the die 36a. Plastically deformed. Further, the knockout 40a is pushed up against the elastic biasing force of the coil spring 42a by the work 2 into which the punch 20a is pushed. By such overhang forming, a convex overhang portion 46 is formed at the center of the work 2.

  When the overhang forming of the workpiece 2 is completed, the lowering of the upper die 14a is stopped, and the upper die 14a is raised in a direction away from the lower die 12a. As a result, the blank holder 22a is pushed up by the elastic biasing force of the coil spring 30a and returns to the original position. Further, the knockout 40a is pushed down by the elastic biasing force of the coil spring 42a to return to the original position, whereby the workpiece 2 left in the opening 44a of the die 36a is pressed downward by the knockout 40a to be die 36a. Is discharged to the outside through the opening 44a. This overhang forming step is performed a plurality of times by different pressing dies 10a such as the outer diameter of the punch 20a and the inner diameter of the opening 44a of the die 36a, thereby gradually reducing the outer diameter of the overhanging portion 46 of the workpiece 2. To do.

  Next, as shown in FIGS. 4 to 8, a compression molding process is performed. A press die 10b used in this compression molding process includes a lower die 12b and an upper die 14b disposed to face the upper side of the lower die 12b. A ring-shaped stopper member 48 is provided on the outer peripheral portion of the upper surface of the blank holder 22b of the lower mold 12b. A ring-shaped stopper protrusion 50 that protrudes toward the upper die 14b is provided on the inner peripheral portion of the stopper member 48 (see FIG. 7). Further, a surplus portion forming recess 52 is provided between the inner peripheral portion of the upper surface of the blank holder 22b and the punch 20b (see FIG. 6). A taper surface 54 is formed on the outer peripheral portion of the surplus portion forming recess 52 so as to gradually reduce the diameter inward in the radial direction of the blank holder 22b. An inclination angle θ (see FIG. 6) of the tapered surface 54 with respect to the horizontal plane is configured to be about 45 °, for example. The tip portion of the punch 20b is configured to have a circular cross section. Further, the outer diameter of the front end portion of the punch 20b is configured to be somewhat smaller than the inner diameter of the opening 24b of the blank holder 22b corresponding to the surplus portion forming recess 52. The other structure of the lower mold 12b is substantially the same as the structure of the lower mold 12a of the press mold 10a described above.

  On the lower surface of the die 36b of the upper die 14b, a ring-shaped receiving recess 56 is provided corresponding to the stopper protrusion 50 of the stopper member 48. Further, the shape of the opening 44b of the die 36b is formed in a circular cross section. The other structure of the upper mold 14b is substantially the same as the structure of the upper mold 14a of the press mold 10a described above.

  The compression molding of the workpiece 2 using the press die 10b described above is performed as follows. As shown in FIG. 4, the workpiece 2 that has been stretched and formed as described above is placed on the upper surface of the blank holder 22 b, and the four corners of the outer peripheral edge thereof are set inside the stopper projection 50 of the stopper member 48. In this state, when the upper die 14b is lowered in the direction approaching the lower die 12b, the outer peripheral portion of the workpiece 2 is pressed and held between the die 36b and the blank holder 22b as shown in FIG. When the upper die 14b is further lowered, the blank holder 22b is pushed down against the elastic biasing force of the coil spring 30b by the die 36b, and the punch 20b is pushed into the overhanging portion 46 of the workpiece 2 through the opening 24b of the blank holder 22b. It is. The overhanging portion 46 of the workpiece 2 into which the punch 20b has been pushed is gradually sucked into the opening 44b of the die 36b, compressed between the punch 20b and the die 36b, and plastically deformed into a cylindrical shape. By compressing the projecting portion 46 of the work 2 in this manner, the cylindrical portion 4 having a closed end is formed on the projecting portion 46 of the work 2. Further, the outer peripheral portion of the work 2 is plastically deformed into a substantially rectangular plate shape by being compressed between the die 36b and the blank holder 22b. By compressing the outer peripheral portion of the work 2 in this manner, a plate-shaped flange having a substantially rectangular shape (specifically, a shape in which the four sides of the rectangle are respectively curved inwardly) is formed on the outer peripheral portion of the work 2. The portion 60 is formed, and the tubular portion 4 rises from the inner peripheral edge of the flange portion 60 (see FIG. 8). Here, the thickness t1 of the cylindrical portion 4 is configured to be approximately 2.0 mm, for example, and the thickness t2 of the flange portion 60 is configured to be approximately 2.6 mm, for example (see FIG. 6). The knockout 40b is pushed up against the elastic biasing force of the coil spring 42b by the work 2 into which the punch 20b is pushed.

  As shown in FIG. 6, during the above-described compression, a part of the material (metal material) constituting the cylindrical portion 4 of the workpiece 2 flows downward and flows into the surplus portion forming recess 52. Become. Thereby, the ring-shaped surplus part 62 which protrudes toward the direction opposite to the cylindrical part 4 is formed over the entire inner peripheral edge part of the flange part 60. The outer peripheral portion of the surplus portion 62 is formed in a tapered shape that gradually decreases in diameter toward the radially inner side of the flange portion 60 by the tapered surface 54 of the surplus portion forming recess 52. Further, as described above, the outer diameter of the tip end portion of the punch 20b is configured to be somewhat smaller than the inner diameter of the opening portion 24b of the blank holder 22b, so the inner peripheral portion of the surplus portion 62 and the tip end of the punch 20b. A gap 64 is formed between the portions.

  Further, during the compression described above, the four corners of the outer peripheral edge of the flange portion 60 are constrained by the stopper protrusions 50 of the stopper member 48 (see FIG. 7), so the outer peripheral edge of the flange portion 60 is in the radial direction. It is prevented from spreading outward. Thereby, it is suppressed that the material which comprises the cylindrical part 4 flows toward the outer peripheral part of the flange part 60, and the material which comprises the cylindrical part 4 flows efficiently to the inner peripheral part of the flange part 60. The surplus portion 62 can be formed efficiently.

  When the compression molding of the workpiece 2 is completed, the lowering of the upper die 14b is stopped, and the upper die 14b is raised in a direction away from the lower die 12b. Thereby, the blank holder 22b is pushed up by the elastic biasing force of the coil spring 30b and returns to the original position. Further, the knockout 40b is pushed down by the elastic biasing force of the coil spring 42b and returned to the original position, whereby the work 2 left in the opening 44b of the die 36b is pressed downward by the knockout 40b and the die 36b. Is discharged to the outside through the opening 44b.

  After the compression molding process, as shown in FIGS. 9 to 11, the drawing process and the flattening process are simultaneously performed. The press die 10c used in this drawing process includes a lower die 12c and an upper die 14c disposed on the upper side of the lower die 12c. On the outer peripheral surface at the tip of the punch 20c of the lower die 12c, a pair of molding recesses 68 are provided corresponding to the pair of recesses 6 formed in the cylindrical part 4 of the workpiece 2 which is the final molded product. Yes. The other structure of the lower mold 12c is substantially the same as the structure of the lower mold 12a of the press mold 10a described above.

  The opening 44c of the die 36c of the upper mold 14c has a circular cross section. Further, at the lower end portion of the opening 44c of the die 36c, an enlarged concave portion 70 that is somewhat enlarged radially outwardly corresponding to the protruding portion 8 formed on the cylindrical portion 4 of the workpiece 2 that is the final molded product. Is provided. The other structure of the upper mold 14c is substantially the same as the structure of the upper mold 14a of the press mold 10a described above.

  Drawing of the workpiece 2 using the press die 10c described above is performed as follows. As shown in FIG. 9, the workpiece 2 compression-molded as described above is placed on the upper surface of the blank holder 22c. When the upper die 14c is lowered in the direction approaching the lower die 12c in this state, the flange portion 60 of the workpiece 2 is sandwiched between the die 36c and the blank holder 22c as shown in FIG. When the upper die 14c is further lowered, the blank holder 22c is pushed down against the elastic biasing force of the coil spring 30c by the die 36c, and the punch 20c is pushed into the cylindrical portion 4 of the workpiece 2 through the opening 24c of the blank holder 22c. It is. The cylindrical portion 4 of the workpiece 2 into which the punch 20c is pushed is gradually sucked into the opening 44c of the die 36c and is squeezed between the punch 20c and the die 36c. By narrowing the tip side of the cylindrical part 4 in this way, a thin part 7 having a small thickness is formed on the tip side of the cylindrical part 4, and the thickness t1 ′ of the thin part 7 is configured to be, for example, about 0.9 mm. Is done. In addition, a pair of concave portions 6 is formed on the outer peripheral surface of the cylindrical portion 4 (thin wall portion 7) by the pair of molding concave portions 68 provided in the punch 20c. Further, as described above, when the distal end side of the cylindrical portion 4 is squeezed, a part of the material constituting the distal end side of the cylindrical portion 4 is flowed to the proximal end side of the cylindrical portion 4, and The proximal end side is increased in thickness to form the thick portion 8. The thickness t3 of the thick portion 8 is configured to be about 2.4 mm, for example. Thus, in the workpiece forming method of the present embodiment, the thickness of the cylindrical portion 4 can be freely controlled by cold press forming. The knockout 40c is pushed up against the elastic biasing force of the coil spring 42c by the cylindrical portion 4 of the work 2 into which the punch 20c is pushed.

  Moreover, when the flange part 60 is compressed between the blank holder 22c and the die 36c, the surplus part 62 formed in the inner peripheral part of the flange part 60 is crushed, and the inner peripheral part of the flange part 60 is It is formed into a flat shape (flattening forming step) (see FIG. 11). As shown by the arrow in FIG. 11, the material constituting the crushed surplus portion 62 is placed on the inner peripheral surface 71 on the proximal end side of the tubular portion 4. Thereby, while the inner peripheral edge 73 of the flange part 60 is shape | molded in edge shape, the smoothness in the inner peripheral surface 71 in the base end side of the cylindrical part 4 is improved, and the surface roughness in this inner peripheral surface 71 is reduced. It can be reduced (for example, the surface roughness Ra is about 1.6 μm).

  When drawing of the workpiece 2 is completed, the lowering of the upper die 14c is stopped, and the upper die 14c is raised in a direction away from the lower die 12c. Thereby, the blank holder 22c is pushed up by the elastic biasing force of the coil spring 30c and returns to the original position. Further, the knockout 40c is pushed down by the elastic biasing force of the coil spring 42c and returned to the original position, whereby the work 2 left in the opening 44c of the die 36c is pressed downward by the knockout 40c and is pressed into the die 36c. Is discharged to the outside through the opening 44c. This drawing process is performed a plurality of times by different pressing dies 10c such as the outer diameter of the punch 20c and the inner diameter of the opening 44c of the die 36c, thereby gradually changing the shape of the workpiece 2 to the shape of the final molded product. Arrange.

  After the drawing process, a first punching process is performed as shown in FIGS. A press die 10d used in this punching molding process includes a lower die 12d and an upper die 14d disposed to face the upper side of the lower die 12d. The lower mold 12d has a lower mold main body 16d and a die 36d provided at the upper end of the lower mold main body 16d. A work accommodating recess 72 having a shape corresponding to the shape of the cylindrical part 4 of the work 2 is provided at the center of the die 36d.

  The upper mold 14d has an upper mold main body 32d, a punch holder 18d provided at the lower end of the upper mold main body 32d, and a punch 20d supported by the punch holder 18d. The punch 20d extends from the punch holder 18d toward the lower mold 12d, and a punching projection 74 is provided at the tip. Further, a blank holder 22d is disposed facing the lower side of the punch holder 18d. An opening 24d is provided at the center of the blank holder 22d, and the tip of the punch 20d is inserted through the opening 24d so as to be movable in the vertical direction. A cushion pin 26d is supported on the upper die body 32d and the punch holder 18d so as to be movable in the vertical direction, and a blank holder 22d is supported on the lower end of the cushion pin 26d. A predetermined pressure is applied to the cushion pin 26d toward the lower mold 12d by air pressure, hydraulic pressure, or the like. The upper die body 32d and the punch holder 18d are provided with a coil spring accommodating recess 28d, and the coil spring accommodating recess 28d accommodates a coil spring 30d. The lower end portion of the coil spring 30d is supported on the upper surface of the blank holder 22d, and the blank holder 22d is elastically biased toward the lower mold 12d by the coil spring 30d. The upper die body 32d is drivingly connected to an elevating mechanism (not shown), and the elevating mechanism causes the upper die 14d to be lowered in the direction close to the lower die 12d or lifted away from the lower die. .

  The punching of the workpiece 2 using the press die 10d described above is performed as follows. As shown in FIG. 12, the cylindrical portion 4 of the workpiece 2 formed by drawing as described above is set in the workpiece accommodating recess 72 of the die 36d. When the upper die 14d is lowered in the direction approaching the lower die 12d in this state, as shown in FIG. 13, the punching protrusion 74 of the punch 20d is driven into the distal end portion of the cylindrical portion 4 of the workpiece 2, thereby The tip of the cylindrical portion 4 is penetrated in a circular shape.

  After the first stamping process, a second stamping process is performed. In the second punching process, as shown in FIG. 1, the flange portion 60 of the workpiece 2 is cut by punching with a press die (not shown). As described above, the forming of the workpiece 2 is completed.

  As mentioned above, although one Embodiment of the shaping | molding method of the workpiece | work according to this invention was described, this invention is not limited to this Embodiment, A various deformation | transformation thru | or correction | amendment are possible without deviating from the scope of the present invention. .

  In the above embodiment, the drawing process and the flattening process are performed at the same time. However, the flattening process may be performed before the drawing process, or after the drawing process. You may comprise so that a planarization shaping | molding process may be performed.

  In the above-described embodiment, the drawing process is performed after the compression molding process, but the ironing process may be performed instead of the drawing process. In this ironing process, the cylindrical portion 4 is formed into a predetermined shape by squeezing the workpiece 2.

  Moreover, in the said embodiment, although it formed so that the surplus part 62 might be formed over the perimeter of the inner peripheral part of the flange part 60 in a compression molding process, it is a part of inner peripheral part of the flange part 60 (namely, The inner edge portion may be formed.

  In the above embodiment, in the compression molding step, the tapered surface 54 that gradually decreases in diameter toward the radially inner side of the blank holder 22b is formed on the outer peripheral portion of the surplus portion forming recess 52. Instead of the tapered surface 54, as shown in FIGS. 14 (a) and 14 (b), it is configured to form rounded surfaces 76A and 76B that gradually decrease in diameter toward the inside in the radial direction of the blank holder 22b. May be. The outer peripheral portion of the surplus portion 62A (62B) is formed in a round shape that gradually decreases in diameter toward the radially inner side of the flange portion 60 by the round surface 76A (76B) of the surplus portion forming recess 52A (52B). Is done. By configuring in this way, the same effects as described above can be achieved.

  Further, in the above embodiment, the four corners of the outer peripheral edge portion of the flange portion 60 are constrained by the stopper member 48. However, when the flange portion 60 is formed into a substantially circular plate shape, the flange portion 60 is used. The entire periphery of the outer peripheral edge portion is restrained by the stopper member 48. Moreover, you may comprise so that the perimeter of the outer peripheral part of the flange part 60 shape | molded by substantially rectangular shape may be restrained by comprising the stopper member 48 in rectangular shape, for example.

  Moreover, in the said embodiment, although it comprised so that the surplus part 62 might be crushed in the planarization shaping | molding process after a compression molding process, a cutting process is performed after a compression molding process, and the surplus part 62 is obtained in this cutting process. You may comprise so that the inner peripheral part of the flange part 60 may be shape | molded flatly by cutting.

2, 2A, 2B, 100 Workpiece 4,104 Cylindrical portion 20a-20d Punch 22a-22d Blank holder 36a-36d Die 46 Overhang portion 48 Stopper member 52, 52A, 52B Recessed portion forming recess 54 Tapered surface 60, 106 Flange 62, 62A, 62B Extra portion 64 Clearance 76 Round surface

Claims (7)

A molding method of a workpiece for molding a workpiece having a cylindrical portion rising from a flange portion and an inner peripheral edge thereof,
An overhang forming step of forming a convex overhang portion on a predetermined portion of a work made of a metal plate, and forming the cylindrical portion in the overhang portion by compressing the work, and forming an outer periphery of the work A compression molding step of molding the flange portion,
In the compression molding step, a surplus portion that protrudes in an opposite direction to the cylindrical portion is formed on an inner edge portion of the flange portion.   The method for forming a workpiece according to claim 1, wherein, in the compression molding step, the surplus portion is formed over the entire circumference of the inner peripheral edge of the flange portion.   A flattening molding step is performed after the compression molding step, and in the flattening molding step, the surplus portion is crushed to shape the inner peripheral edge of the flange portion into a flat shape. Item 3. A method for forming a workpiece according to Item 2. In the compression molding step, a punch, a blank holder that is movably mounted on the punch in a vertical direction, and a die that is disposed to face the blank holder are used. A surplus part forming recess for forming the surplus part is provided in between, and the outer peripheral part of the surplus part forming recess gradually decreases inward in the radial direction of the blank holder. It is formed in a taper shape or a round shape,
When compressing the workpiece, the outer peripheral portion of the workpiece is pressed and held between the die and the blank holder, and the punch is pushed into the overhanging portion of the workpiece, whereby the overhanging portion is When the cylindrical part is molded, the flange part is molded on the outer peripheral part of the work, and the material constituting the work flows into the surplus part forming concave part, whereby the inner peripheral part of the flange part is 4. The workpiece forming method according to claim 2, wherein a surplus portion is formed.   In the compression molding step, when the surplus portion is formed in the recess for forming the surplus portion, a gap exists between the inner peripheral portion of the surplus portion and the punch. Item 5. A method for forming a workpiece according to Item 4.   In the compression molding step, at least a part of the outer peripheral edge portion of the flange portion is restrained by a stopper member, thereby preventing the outer peripheral edge portion of the flange portion from expanding radially outward when the workpiece is compressed. The method for forming a workpiece according to any one of claims 1 to 5, wherein: A molding method of a workpiece for molding a workpiece having a cylindrical portion rising from a flange portion and an inner peripheral edge thereof,
An overhang forming step of forming a convex overhang portion on a predetermined portion of a work made of a metal plate, and forming the cylindrical portion in the overhang portion by compressing the work, and forming an outer periphery of the work A compression molding step for molding the flange portion, and a drawing or ironing step for molding the tubular portion into a predetermined shape by squeezing or squeezing the workpiece,
In the drawing process or the ironing process, part of the material constituting the distal end side of the cylindrical part flows to the proximal end side of the cylindrical part by squeezing or squeezing the distal end side of the cylindrical part. And the thickness of the tubular portion on the proximal end side is increased to form a thick portion on the proximal end side of the tubular portion, and the thickness on the distal end side of the tubular portion is decreased to reduce the thickness of the tubular portion. A method for forming a workpiece, characterized in that a thin-walled portion is formed on the tip side of a cylindrical portion.

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