JP2010253513A - Method for forming undercut part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming an undercut part which achieves shortening of the working steps and the working time, and reduction in the required area for equipment, and contributes to saving energy. <P>SOLUTION: The method for forming the undercut part includes a first press-working step of forming a wall surface part 10a on a metal plate 5 in a direction crossing the surface of the metal plate, a second press-working step of forming a thickened part 11a on the wall surface part by coining a part in a vicinity of the wall surface part on the surface part of the metal plate, and a third press-working step of forming an undercut part 1a by pressing the thickened part by a punch. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for forming an undercut portion using press molding, a method for manufacturing a component having an undercut portion, and a press-worked component manufactured by the manufacturing method.

  As a conventional method for manufacturing a part having an undercut portion, an intermediate part having a cylindrical wall is formed by pressing from a metal plate material, and then an annular part having an inner diameter concave portion that becomes an undercut is formed on the inner periphery of the cylindrical wall. A manufacturing method, in which a punch of a press machine is pushed into the inner periphery of the cylindrical wall to expand the inner diameter of the cylindrical wall to an inner diameter corresponding to the inner diameter recess, and the inner diameter of the cylindrical wall is changed from the root side to the tip side. In some cases, there is a squeezing step of squeezing a cylindrical wall into a tapered shape using a tapered punch so as to gradually become smaller (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2007-125614 (first page, FIG. 1)

  In the prior art as described above, although it can be dealt with only by pressing, the plate-like material is first punched into a disk shape, so individual conveyance is required in the subsequent process. Further, since the entire circumference is punched on the outer diameter side, there is a problem that a fracture surface is formed and an additional process for chamfering is required.

  The present invention has been made to solve the above-described problems of the prior art, and can be integrally formed by press molding with a progressive die, which eliminates the need for additional steps, shortens the processing time, and reduces the cost of the product. It is an object of the present invention to provide a method for forming an undercut portion that can be provided, a method for manufacturing a component having an undercut portion, and a pressed part manufactured by the manufacturing method.

In the undercut portion forming method according to the present invention, after the thickened portion is formed by coining with a press, the undercut portion is formed by pressing the thickened portion with a punch.
Moreover, the manufacturing method of the component which has an undercut part which concerns on this invention press-molds the component which has an undercut part using the formation method of the undercut part which becomes the said this invention.
Moreover, the press-worked part which concerns on this invention is manufactured using the manufacturing method of the component which has the undercut part which becomes the said this invention, It is characterized by the above-mentioned.

In the undercut portion forming method of the present invention, the thickened portion for forming the undercut portion by coining is formed, and the undercut portion is formed by pressing the thickened portion with a punch. It can correspond to various processing shapes. Moreover, it becomes possible to stabilize the shape and dimension of an undercut part.
In addition, according to the method for manufacturing a part having an undercut portion according to the present invention, it is possible to perform integrated press molding by a progressive die, so that an additional process can be eliminated, processing time is shortened, and a product is inexpensive. Can be provided. In addition, it is possible to manufacture a component in which the shape and dimensions of the undercut portion are stable.
Moreover, the press-worked part which concerns on this invention has the shape and dimension of an undercut part stable, and has improved quality.

Sectional drawing explaining the example at the time of applying the formation method of the undercut part which concerns on Embodiment 1 of this invention, and the manufacturing method of the component which has an undercut part to the press molding of the stop collar used for the starter for engine starting It is. It is sectional drawing explaining the press molding process of the stop collar shown by FIG. 1 in order of a process with a main press molding die. It is a fragmentary sectional view explaining the use condition of the stop collar obtained by the method shown by FIG.

Embodiment 1 FIG.
Hereinafter, a method for forming an undercut portion according to Embodiment 1 of the present invention, a method for manufacturing a component having an undercut portion, and a press-worked component manufactured by the manufacturing method will be described with reference to FIGS. explain. As shown in FIG. 3, a ring-shaped stop collar 1 which is an example of a press-worked part obtained by the method of the present invention has an undercut portion 1a on the inner peripheral portion, and is an output shaft of an engine starter. 2 through a snap ring 3. The stop collar 1 is used as a movement restricting means for restricting the position of the pinion 4 disposed on the output shaft 2 when the pinion 4 moves to the ring gear side (left side in the figure) of the engine. Hereinafter, the case where the above stop collar 1 is press-molded by a progressive die will be specifically described in the order of the main steps.

Step 1. As shown in Fig. 1 and Fig. 2 (1), it is unnecessary to set the plate material 5 made of a thick metal plate material on a press machine corresponding to the progressive die and absorb the escape during the pressing process. A circular pilot hole 6 is opened at a position corresponding to the portion (not shown) and the radial center of the finished product.
In addition to the punch, a product pressing mechanism and a transfer means for the plate material 5 as a workpiece are attached to all the processes including this process. However, the pressing mechanism and the transferring means are simply used for a normal press. The illustration is omitted together with a punch for punching a hole and a press machine. In addition, the plate 5 is a long one in which the parts to be processed are continuous at a predetermined interval, as in the case of press molding by a general progressive die, but in order to facilitate the understanding of the invention, it is made into one finished product. Only the corresponding parts are shown.

Step 2. Preliminary forming process in which an unnecessary portion around the pilot hole has a concave shape As shown in FIG. 2 (2), a hole 81a having a diameter larger than that of the pilot hole 6 is formed coaxially with the position of the pilot hole 6. After the plate material 5 is moved to the lower die 81 in which the 81b has been R-processed, the plate material 5 is pressed by the upper punch 91 having a protrusion 91a having a diameter larger than the hole 81a by a predetermined dimension, as shown in FIG. A preforming portion that is an intermediate product of the processed shape is formed.
As a result, a convex portion 72 corresponding to the shape of the hole 81 a provided in the lower die 81 is formed on the lower surface of the plate material 5, and a concave portion 71 corresponding to the protruding portion 91 a of the upper punch 91 is formed on the upper surface of the plate material 5. . In this case, the pilot hole 6 serves as a reference hole, and the concentric recess 71 formed after punching the pilot hole 6 is used to escape an unnecessary part. Since the concave portion 71 is not restrained in the pressing process, the deformation load can be released and the pressing load can be reduced.

Step 3. Molding of the wall surface part to be the inner peripheral side part (first pressing process)
As shown in FIG. 2 (3), a plate material is provided on the lower die 82 having a circular recess 82a having a larger diameter than the hole 81a and having a hole 82b having the same shape and size as the hole 81a at the center. 5 is moved, and then a convex portion 92a for forming the concave portion 10 to be the inner peripheral side portion of the stop collar 1 is formed, and the outer peripheral portion 92b at the tip end of the convex portion 92a is R-processed to a predetermined dimension. A wall surface 10a is formed on the inner peripheral surface of the recess 10 in the direction intersecting the extending direction of the surface of the plate 5 shown in FIG.
The upper side in the figure of the wall surface portion 10a forming the concave portion 10 is formed so as to be connected to the surface of the plate member 5 by drawing a smooth arc, and a thickened portion is formed on the wall surface portion 10a in the next step. The Moreover, the lower end part side of the wall surface part 10a is formed in an R shape, and the R-shaped part finally becomes the lower half part of the concave part of the undercut part 1a. In this step 3, the concave portion 10 is molded on the outer peripheral side avoiding the concave portion 71 on the central portion side around the pilot hole 6 preliminarily molded in the above step 2, thereby reducing the molding load. Further, it is possible to mold any chamfered shape in the shape of the bottom outer peripheral side corner portion 82c of the circular concave portion 82a of the lower die 82.

Step 4. Coining process (second press process)
As shown in FIG. 2 (4), after the plate material 5 is moved to the lower die 83 in which the concave portion 83a having the same shape and size as the lower die 82 is formed, the outer peripheral portion of the pressing surface 93a is substantially wedge-shaped in cross section. The convex portion 93b is pressed by an upper punch 93 formed so as to draw a circle, and a circular shape having a substantially V-shaped cross section is formed around the upper surface of the plate 5 at the edge portion of the concave portion 10 as shown in FIG. A groove 11 is formed.

  This processing step is a preforming step for forming an undercut portion, and for forming an undercut portion in a portion extending from the inner peripheral side of the groove 11 to the wall surface portion 10a by the wedge effect by the convex portion 93b of the upper punch 93. The thickened portion 11a is formed. Combined with the fact that the bottom outer peripheral end of the recess 10 is formed in an R shape in the previous step (step 3), the undercut of an inner diameter recess that is rounded and recessed at the bottom of the thickened portion 11a The part formation scheduled part 11b is formed. The convex portion 93b having a substantially wedge-shaped cross section of the upper punch 93 has a large inclination angle on the outer peripheral side and a gentle inclination angle on the inner peripheral side, and the thickened portion 11a is easily formed in the central portion O direction. The Moreover, the flat pushing load of the process 5 can be reduced by the wedge effect.

Step 5. Coining part flat pressing with constrained inner diameter (third press working process)
As shown in FIG. 2 (5), after the plate material 5 is moved to a lower die 84 having the same shape and size as the lower die 82, a flat surface forming portion 94a is provided on the outer peripheral portion, and a taper is provided on the central portion side. The coining portion having the thickened portion 11a is flat-molded by an upper punch 94 having a chamfered shape forming portion 94b and a protrusion 94c provided further on the center side than the chamfered shape forming portion 94b. Processing into the shape shown in 1 (5).

  In this step, the central surface side from the inner peripheral wall of the groove 11 having a V-shaped cross section formed by the coining of the previous step is flat pressed by the flat surface forming portion 94a in a state where the inner diameter is constrained by the chamfered shape forming portions 94b and 94c. 1 to form the flat surface portion 12a of FIG. 1 (5), and the thickened portion 11a is plastically deformed in the downward direction of the drawing, and the chamfered shape portion 12b and the undercut portion are formed on the center portion side of the flat surface portion 12a. 1a is formed. Further, the shape of the chamfered shape portion 12b can be arbitrarily formed by the chamfered shape forming portion 94b. In addition, although the upper side punch 94 which has the plane formation part 94a and the chamfering shape formation part 94b was used, it is not limited to this. For example, the flat surface forming portion 94a may include an inclination or a curve, and the flat surface forming portion 94a and the chamfered shape forming portion 94b may be formed with a processed surface having a continuous curve.

Step 6. Next, the unnecessary portion 51 of the inner diameter portion surrounded by the alternate long and short dash line A in FIG. 1 (5) is extracted by the lower die and the upper punch which are not shown in the drawing, and shown in (6) in FIGS. It is set as the shape which has the processed surface part 13 to show.

Step 7. Outside Diameter Half-Punching Process After the plate material 5 is moved to the lower die 85 having a hole 85a for half-cutting the outer diameter portion shown in FIG. 2 (7), a cylindrical upper punch 95 for half-punching is used. The outer diameter half-cutting process is performed, and the corner portion 14 formed by shearing is formed into a dimension capable of shaving in the next process, as shown in FIG. 1 and FIG. 2 (7). By the step 3 and the step 7, the shear surface of the outer peripheral portion is secured. Moreover, it becomes possible to reduce a press load by dividing a process.

Step 8. Outer diameter shaving processing As shown in FIG. 1 and FIG. 2 (8), a stop collar 1 that is a pressed product completed from an unnecessary portion 52 connected to the plate material 5 is formed by pressing with a shaving punch (not shown). Pull out.

  The undercut portion forming method according to the first embodiment includes a first press working step (step 3) for molding the wall surface portion 10a to be an inner peripheral portion, and a thickened portion for forming the undercut portion by coining. A second press working step (step 4) for forming 11a, and a third press working step (step 5) for forming the undercut portion 1a by pressing the increased thickness portion 11a with the upper punch 94. Is. According to the first embodiment, since the thickened portion 11a for forming the undercut portion is formed by coining, it is possible to cope with various processed shapes. In addition, after the thickened portion 11a is formed, when the upper punch 94 is pressed, the undercut portion 1a is molded in a state where the inner diameter portion of the thickened portion 11a is constrained by the chamfered shape forming portions 94b and 93c Therefore, the convex part dimension and concave part shape of the undercut part 1a are stabilized. Moreover, the load at the time of shape | molding the undercut part 1a is reduced.

  Moreover, the manufacturing method of the component which has the undercut part which concerns on the said Embodiment 1 continues the preforming process (process 2) which processes the unnecessary part around the pilot hole 6 into the recessed part 71, and the above-mentioned undercut part. It is manufactured using a forming method. According to the manufacturing method, the unnecessary portion of the central portion is formed in the concave portion 71 by preforming to substantially reduce the plate thickness at the time of pressing in the next process, so that the punching load is reduced. The mold contact area is reduced by pressing the mold only on the product portion, and the press load can be reduced.

  In addition, since it is possible to reduce the fracture surface and to perform integrated press molding with a progressive die, it is possible to mold the undercut part without performing cold forging or cutting, thus eliminating the need for additional processes and processing time. Is also shortened. Furthermore, by reducing the number of man-hours, products can be supplied at a low cost, and the required area for equipment can be reduced, contributing to energy savings and reducing environmental burdens in production processes. Further, the shape of the bottom outer peripheral corner portion 82c of the circular recess 82a of the lower die 82 shown in FIG. 2 (3) and the chamfered shape portion 94b of the upper die 94 shown in FIG. A chamfered shape can be formed. In addition, the coining in step 3 in FIG. 2 not only reduces the load of thickening molding of the undercut portion, but also reduces the plate thickness in the outer diameter half-punching step in step 7 and can reduce the half-pumping load. . Furthermore, the process of extracting the outer diameter is divided into the half-drawing process of process 7 and the shaving process of process 8, so that it is easy to reduce the load and secure a shear plane in the shaving process of the next process.

  Moreover, the stop collar 1 which is a press-worked part obtained by the integrated processing of the press by the progressive die according to the first embodiment has a third thickening portion 11a as an undercut portion formed by coining. When the undercut molding is performed in the press working process, the inner diameter portion is constrained, so that the convex size and the concave shape of the undercut portion 1a are stable, and the quality is excellent. In addition, since it is formed by integrated processing of a press by a progressive die, it can be provided at low cost by reducing processing time and man-hours.

  In the first embodiment, the punch having the convex portion 93b having the wedge shape in cross section is used when forming the thickened portion by coining. However, the shape of the convex portion 93b is not necessarily limited to the wedge shape in cross section. Other shapes can be used as long as the thickened portion can be formed. Further, the order of processing steps, processing details, and the like are not limited to those exemplified in the first embodiment. Moreover, there is no special restriction | limiting also in the kind of board | plate material, thickness, etc. For example, it can select from a well-known general various material suitably, and can use it. In the first embodiment, the case where the present invention is used for manufacturing the ring-shaped stop collar 1 used for the starter for starting the engine has been described. However, the shape, structure, use, and the like of the workpiece are limited to this. It goes without saying that it is not done. As long as it is necessary to form the undercut portion, it is not limited to a ring-like shape such as a ring shape, and can be widely applied in correspondence with, for example, an arbitrary shape combined with a polygonal shape or a curve.

  1 Stop collar (pressed parts), 1a Undercut part, 2 Output shaft, 3 Snap ring, 4 Pinion, 5 Plate material, 51 Unnecessary part, 52 Unnecessary part, 6 Pilot hole, 71 Concave part, 72 Convex part, 81 Lower side Die, 81a hole, 81b edge, 82 lower die, 82a circular recess, 82b hole, 82c bottom outer corner, 83 lower die, 83a recess, 84, 85 lower die, 85a hole, 91 upper punch, 91a Projection, 92 Upper punch, 92a Convex, 92b Tip outer periphery, 93 Upper punch, 93a Pressure surface, 93b Convex, 94 Upper punch, 94a Plane formation, 94b Chamfered shape formation, 94c Projection, 95 Upper punch , 10 concave portion, 10a wall surface portion, 11 groove, 11a thickened portion, 1 b undercut portion formation portion, 12a flat portion, 12b chamfered portion 13 machined surface, 14 corner.

Claims (8)

  A method of forming an undercut portion in which an increased thickness portion is formed by coining with a press and then the undercut portion is formed by pressing the increased thickness portion with a punch.   A first pressing step of forming a wall surface portion in a direction intersecting the surface direction of the plate material on the plate material; a second step of forming a thickened portion on the wall surface portion by coining the vicinity of the wall surface portion of the surface of the plate material; 2. The undercut portion forming method according to claim 1, further comprising: a third press working step of forming an undercut portion by pressing the increased thickness portion with a punch.   3. The method of forming an undercut portion according to claim 2, wherein in the third press working step, the thickened portion is performed in a state constrained by an upper punch.   Before the first press working step, the method includes a preforming step of forming a recess for releasing an unnecessary portion with reference to the reference hole after punching a reference hole in the plate material by press punching. The method for forming an undercut portion according to claim 2 or 3.   The undercut according to any one of claims 2 to 4, wherein an upper punch having a convex portion along a product shape for forming the wall surface portion is used in the first press working step. Part forming method.   A method for producing a part having an undercut part, comprising press-molding a part having an undercut part using the undercut part forming method according to any one of claims 1 to 5.   The method for producing a part having an undercut part according to claim 6, wherein the part having an undercut part is molded from a metal plate material by integrated processing using a press progressive die.   A press-worked part having an undercut portion, which is manufactured according to claim 6 or 7.

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