JP5084491B2 - Double-sided protruding cylindrical part molding method from flat plate and double-sided protruding cylindrical part integrally molded product - Google Patents

Description

  The present invention relates to a method for forming a double-sided protruding cylindrical part from a flat plate, and a double-sided protruding cylindrical part integrally molded product.

  2. Description of the Related Art Conventionally, a flat plate (a flat metal plate) or the like is processed to form, for example, a cylindrical bearing and a bearing holder on a part of the flat plate.

  Conventional conventional forming means include forming a cylindrical part in a predetermined shape by cutting out from a thick plate or cutting a round bar, crushing a hollow slag material from the vertical direction, and forming a cylindrical part in a predetermined shape. Known are molding, molding of a cylindrical portion of a predetermined shape by cold forging, and the like.

  However, even if these conventional forming means are employed, it is extremely difficult to form cylindrical bearings and bearing holders that protrude from both sides of the flat plate material. In addition, it has been extremely difficult to form cylindrical bearings and bearing holders that protrude from both sides of a flat plate material by press molding.

  Patent Document 1 proposes a carrier gear manufacturing method in which a processed portion is crushed by pressing from the upper surface side of the processed portion to form a thin plate portion, a bearing recess, a planetary gear shaft, and the like. .

However, even in Patent Document 1, cylindrical bearings and bearing holders that protrude on both sides of a flat plate material are not formed by press working.
JP 2004-337926 A

  The problem to be solved by the present invention is a method of forming a double-sided protruding cylindrical part from a flat plate by integrally forming a cylindrical part protruding from both sides of the flat plate (for example, a cylindrical part constituting a bearing and a bearing holder) by pressing, and There is no double-sided protruding cylindrical part integrally formed product by press working.

The present invention relates to a method for forming a double-sided protruding cylindrical portion from a flat plate by integrally processing a protruding cylindrical portion protruding from both sides by processing a flat plate material, and a blank for forming a flat plate blank having a circular center hole from a flat plate material A punching step, a molded part for a double-sided protruding cylindrical part that swells in a trapezoidal cross-section toward the one side for the required thickness at the center part of the flat plate blank, an outer peripheral side flat part that is thinner than the thickness of the flat plate blank, A pre-processing press molding step for forming a raised portion on the entire edge, a bottomed cylindrical portion having a predetermined inner diameter projecting to one surface side with respect to the molded portion for the double-sided protruding cylindrical portion, and a bottomed cylindrical portion A first overhanging press forming process in which a taper-shaped crushing process for securing a wall thickness is performed on the overhang end surface, and a bottom hole for overhanging to the other surface side with respect to the bottomed cylindrical portion subjected to the taper-shaped crushing process. Provide A blanking press forming step, and bulging and forming toward the other side while leaving a predetermined thickness based on the maximum diameter of the tapered crushing portion with respect to the bottomed cylindrical portion, and an outer taper on one side The preliminarily cylindrical part connected to one surface of the flat plate blank through the part, and the oppositely bulging bottomed cylindrical part connected to the other surface of the flat plate blank while the end face is flat on the other surface side and the outer peripheral edge is rounded. The second overhanging press forming process for projecting molding, the restructuring process for forming the preliminarily cylindrical portion and the bulging bottom cylindrical portion in the opposite direction into a product size shape to form a double-sided projecting cylindrical portion, and the product size shape a vent hole press-molding process by molding the vent hole of predetermined dimension in a direction opposite bulging bottomed cylindrical portion, forming a circular flange portion serving as an inner circumferential side to the projecting projecting blind shape in the two-sided protrusion cylindrical portions, the Inclusion is the main feature.

According to the first aspect of the present invention, for example, a bearing and a bearing holder provided with a circular flange portion that protrudes from one side and the other side at the center and has a fixed shape based on a flat plate blank through the series of steps described above. It is possible to provide a method of forming a double-sided protruding cylindrical part from a flat plate that can reliably form the double-sided protruding cylindrical part to be formed only by press molding.

According to the second aspect of the invention, as in the case of the first aspect of the invention, the circular shape that goes through the above-described series of steps and protrudes from one side to the other side and the other side at the center, based on the flat plate blank. For example, it is possible to provide a method of forming a double-sided protruding cylindrical part from a flat plate, which can reliably form a double-sided protruding cylindrical part that constitutes, for example, a bearing and a bearing holder provided with a flange only by press molding.

According to a third aspect of the present invention, for example, a bearing and a bearing holder provided with a circular flange that protrudes from one side and the other side at the center and has a stationary shape based on a flat plate blank through the series of steps described above. The double-sided projecting cylindrical part is formed from a flat plate that can reliably form a double-sided projecting cylindrical part integrally formed product with a flat part on the outer peripheral side having a plurality of circularly arranged protrusions on the outer peripheral side only by press molding. A method for forming a double-sided protruding cylindrical part can be provided.

According to invention of Claim 4, it protrudes in one side and other surfaces in the center part of a circular flat plate material, and it is demarcated by the circular punched hole in the protrusion edge part of the other surface side, and protrudes and stops on the inner peripheral side. Since the double-sided protruding cylindrical part having the circular flange part having the shape is provided, it is possible to provide a double-sided protruding cylindrical part integrated molded article that is suitable for use in bearings and bearing holders.

According to the fifth aspect of the invention, as in the fourth aspect of the invention, a circular flat plate is projected at one central portion of the circular flat plate on both one side and the other side , and a circular punched hole is formed at the protruding end on the other side. By providing the double-sided protruding cylindrical part having a circular flange that protrudes to the inner peripheral side and has a stop shape, a double-sided protruding cylindrical part-integrated product suitable for use in bearings and bearing holders can be provided.

According to invention of Claim 6, it protrudes in one side and other surfaces in the center part of a circular flat plate material, and it is demarcated by the circular punched hole in the protrusion edge part of the other surface side, and protrudes and stops on the inner peripheral side. Since the double-sided protruding cylindrical portion having a circular flange portion that has a shape is provided with a plurality of circularly-arranged protrusions having a cross-sectional convex-shaped concave hole protruding from the one surface side on the outside thereof, as a bearing and a bearing holder, etc. Therefore, it is possible to provide a double-sided protruding cylindrical part-integrated product suitable as a member capable of transmitting power to the element.

  An object of the present invention is to provide a method for forming a double-sided protruding cylindrical part from a flat plate that integrally forms, for example, a cylindrical part constituting a bearing and a bearing holder protruding from both sides of the flat plate by pressing.

The present invention is a method of forming a double-sided protruding cylindrical part from a flat plate by integrally processing a protruding cylindrical part protruding from both sides by processing a flat plate material, and is a flat blank having a circular shape and a center hole from the flat plate material A blank blanking step for forming a flat plate blank, a molded part for a double-sided protruding cylindrical part that rises in a trapezoidal cross section to the required thickness side at the central part of the flat plate blank, and an outer peripheral flat part that is thinner than the thickness of the flat blank in its outer region A pre-processing press molding step for forming a raised portion on the entire outer peripheral edge of the other surface, and forming a bottomed cylindrical portion having a predetermined inner diameter projecting to one side with respect to the molded portion for the double-sided protruding cylindrical portion, A first overhanging press forming process in which a taper-shaped crushing process for securing a wall thickness is performed on the projecting end surface of the bottom cylindrical part, and a bottomed cylindrical part subjected to the taper-shaped crushing process for projecting to the other surface side Bottom out A bottomed press forming step for providing a hole, and a swelled molding toward the other surface side while leaving a predetermined thickness based on the maximum diameter of the tapered crushing portion with respect to the bottomed cylindrical portion, A preliminarily cylindrical portion connected to one surface of the flat plate blank through the outer tapered portion on the side, and a reverse-side-extended bottomed cylinder connected to the other surface of the flat plate blank while the end surface is flat and the outer peripheral edge has an R shape on the other surface side A second overhanging press forming step for integrally projecting the portion, a pre-cylindrical outer side press forming step for forming the outer tapered portion of the pre-cylindrical portion into an R shape, and the pre-cylindrical portion integrally connected to the reverse cylindrical portion. A first wrist-like process in which the bottomed cylindrical part is formed into a product-sized shape to form a double-sided protruding cylindrical part, and the projecting end inner peripheral part of the preliminary cylindrical part that has become a product-sized shape, The second restructuring that forms the inner peripheral edge part into each R shape And click process, shaping the vent hole of predetermined dimension in a direction opposite bulging bottomed cylindrical portion of the double-sided protruding cylindrical portion became product dimensions, forming a circular flange portion serving as a protruding blind shape on the inner peripheral side This is realized by a configuration including a punched hole press forming step.

  Hereinafter, a method for forming a double-sided protruding cylindrical portion from a flat plate according to an embodiment of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the method of forming a double-sided protruding cylindrical part from a flat plate according to the present embodiment is a circular hole (disc-like) center hole formed from a flat plate material made of hot-rolled steel or the like, as shown in FIG. A flat blank 1 having 2 is formed.

  Next, as a pre-processing press molding step, as shown in FIG. 2, a double-sided protruding cylinder that rises in a trapezoidal shape in cross section toward the surface (lower surface in FIG. 2) by a necessary thickness at the center of the flat blank 1 using a mold. The molded part 3 for the part is thinner than the thickness of the flat blank 1 in the outer region, and the outer peripheral side flat part 4 having the required thickness is formed on the outer peripheral edge of the other peripheral surface (upper surface in FIG. 2). The raised portion 5 is formed to suppress the sagging amount.

  Next, as shown in FIG. 3, the first projecting press molding process has a predetermined inner diameter projecting to the one surface side using a molding die with respect to the molding part 3 for the double-sided protruding cylindrical part, and the outer periphery is substantially tapered. The bottomed cylindrical portion 6 having a surface shape is stretched and molded, and the tapered crushing portion 7 for securing the thickness is processed on the projected end surface of the bottomed cylindrical portion 6. This taper-shaped crushing portion 7 serves to ensure the thickness of the overhanging outer periphery and to promote the introduction of the forming punch in the next process.

  Next, as a bottomed press molding process, as shown in FIG. 4, the bottomed cylindrical portion 6 in which the tapered crushing portion 7 is processed is used for projecting to the other side using a molding punch. The bottom hole 8 is punched out.

  Next, as a second overhang press forming step, as shown in FIG. 5, a predetermined thickness based on the maximum diameter of the tapered crushing portion 7 using a forming die for the bottomed cylindrical portion 6 is used. While remaining, the bulging process is performed with a press toward the other side. As a result, the preliminary cylindrical portion 9 connected to one surface of the flat plate blank 1 through the outer tapered portion 9a on one surface side, the other surface of the flat plate blank 1 while the end surface is flat and the outer peripheral edge portion 10a has an R shape. The oppositely bulging bottomed cylindrical portion 10 that is connected to is integrally formed by projecting. The outer tapered portion 9a exhibits a function of preventing cracks during press molding.

  Next, as shown in FIG. 6, as the preliminary cylindrical portion outer press forming step, the outer tapered portion 9a of the preliminary cylindrical portion 9 is press-molded into an R-shaped portion 9b.

  Next, as shown in FIG. 7, as the first restructuring process, the preliminary cylindrical portion 9 and the reversely expanded bottomed cylindrical portion 10 that are integrally connected are press-molded into a product size shape using a molding die. These are the desired double-sided protruding cylindrical portions 11.

  Next, as a second wrist-like process, as shown in FIG. 8, the protruding end inner peripheral portion 9 c of the preliminary cylindrical portion 9 in the double-sided protruding cylindrical portion 11 having a product size shape, a reversely expanded bottomed cylindrical portion 10 inner bottom peripheral edge portions 10b are each press-molded into an R shape using a molding die.

  Next, as shown in FIG. 9, as a punching hole press forming step, a circular punch with a predetermined dimension is formed by using a forming punch in the oppositely bulging bottomed cylindrical portion 10 in the double-sided protruding cylindrical portion 11 having a product size shape. A punched hole 12 is formed, and a circular flange 13 protruding toward the inner peripheral side is press-molded. The wall thickness of the circular flange 13 is set to be thinner than the wall thickness of the double-sided protruding cylindrical portion 11.

  Next, as shown in FIG. 10, as a protrusion press molding process, the outer peripheral side flat portion 4 is projected to a predetermined position on the outer surface side by using a molding die, and a concave section having a convex cross section from one surface side is formed therein. A plurality of circularly arranged projections 14 having holes 15 are press-molded. Further, a long hole 16 is formed at a predetermined position of the outer peripheral side flat portion 4 to form a double-sided protruding cylindrical portion integrated product 20. Thereafter, roughing, half-cutting, and finish-cutting are executed.

  Such a shape of the protrusion 14 having the concave hole 15 minimizes a reduction in the plate thickness of the outer peripheral flat portion 4 and ensures the strength of the joint portion between the protrusion 14 and the outer flat portion 4. Further, it is possible to prevent cracking during heat treatment performed later.

  Thus, according to the double-sided protruding cylindrical part molding method from the flat plate according to the present embodiment, a circular shape protrudes from one side and the other side at the center part based on the flat plate blank 1 by the series of steps described above. The double-sided protruding cylindrical part 11 including the flange part 13 is provided with an outer peripheral side flat part 4 having a plurality of circularly arranged protrusions 14 on the outer peripheral side thereof. 20 can be reliably molded only by press molding.

The double-sided protruding cylindrical part integrated molded product 20 is then subjected to heat treatment or the like to become a product.
According to the double-sided protruding cylindrical part integrated molded product 20 according to the present embodiment formed as described above, the outer periphery in which the double-sided protruding cylindrical part 11 is circularly arranged at the center part and the protrusion 14 is circularly arranged on the outer peripheral side is circular. The side flat part 4 is integrally provided, and the double-sided protruding cylindrical part 11 in particular has a so-called stop shape including a circular flange part 13 opened on one side and defined by a circular punching hole 12 on the other side. It is said.

  Therefore, this double-sided protruding cylindrical portion 11 can be used as a bearing holder portion having a large holding force for the cylindrical bearing, and in this case, the circular flange portion 13 can function as a retainer for retaining the cylindrical bearing and for press-fitting positioning. .

  Next, a specific use example of the double-sided protruding cylindrical part integrated molded product 20 will be described with reference to FIGS. 11 to 13.

  That is, the teeth 31a are engraved at regular intervals on the outer peripheral portion of the double-sided protruding cylindrical part integrated product 20 as shown in FIGS. 11 and 12 to form a sun gear (cycloid gear) 31, and the double-sided protruding cylinder as shown in FIG. A bearing 32 that supports the rotary shaft 40 is press-fitted into the portion 11 so that the rotary shaft 40 passes through the center of the sun gear 31, and the internal teeth 33 a of the external gear (cycloidal gear) 33 are inserted into the teeth 31 a of the sun gear 31. Further, a gear reduction mechanism with a motor that engages with the end face of the rotor 34 of the motor and enables transmission of power between the sun gear 31 and the rotor 34 is shown. is there.

  According to the sun gear 31 obtained by processing such a double-sided protruding cylindrical part integrally molded product 20, the double-sided protruding cylindrical part 11 holds the bearing 32 while securely and preventing it from coming off and meshes with the external gear 33. It can rotate accurately. Further, the projection 14 can smoothly transmit power between the sun gear 31 and the rotor 34.

  The double-sided projecting cylindrical part integrally molded product of the present invention can be widely applied as a bearing and bearing holder part of motors, pumps, and other various devices, in addition to being applied to a gear having the bearing and bearing holder part as described above. is there.

It is a top view which shows the flat plate blank in the double-sided protrusion cylindrical part shaping | molding method from the flat plate which concerns on the Example of this invention. It is sectional drawing which shows the shaping | molding process of the shaping | molding part for double-sided protruding cylindrical parts, the outer peripheral side flat part, and the raising part in the double-sided protruding cylindrical part shaping | molding method from the flat plate which concerns on a present Example. It is sectional drawing which shows the shaping | molding process of a bottomed cylindrical part and a taper-shaped crushing part in the double-sided protrusion cylindrical part shaping | molding method from the flat plate which concerns on a present Example. It is sectional drawing which shows the punching process of the bottom hole 8 in the double-sided protrusion cylindrical part shaping | molding method from the flat plate which concerns on a present Example. It is sectional drawing which shows the pre-cylindrical part in the double-side protrusion cylindrical part shaping | molding method from the flat plate which concerns on a present Example, and the shaping | molding process of a reverse facing bulging bottomed cylindrical part. It is sectional drawing which shows the process of shape | molding the outer side taper part in the R-shaped part in the double-sided protrusion cylindrical part shaping | molding method from the flat plate which concerns on a present Example. It is sectional drawing which shows the formation process of the double-sided protruding cylindrical part in the double-sided protruding cylindrical part shaping | molding method from the flat plate which concerns on a present Example. Sectional drawing which shows the process of shape | molding the inner peripheral edge part of the protrusion end inner peripheral part of a preliminary | backup cylindrical part and the inner bottom peripheral part of a reverse bulging bottomed cylindrical part in the double-sided protrusion cylindrical part formation method from the flat plate which concerns on a present Example, respectively. It is. It is sectional drawing which shows the formation process of the punching hole with respect to the reverse bulging bottomed cylindrical part in the cylindrical part molding method from a flat plate which concerns on a present Example, and a circular collar part. It is sectional drawing which shows the shaping | molding process which shape | molds the processus | protrusion which has a convex-shaped recessed hole in the double-sided protrusion cylindrical part shaping | molding method from the flat plate which concerns on a present Example. It is a top view of the sun gear based on the double-sided protruding cylindrical part integral molded product which concerns on a present Example. It is sectional drawing of the sun gear based on the double-sided protrusion cylindrical part integral molded product which concerns on a present Example. It is sectional drawing which shows the usage example of the sun gear which concerns on a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flat plate blank 2 Center hole 3 Molding part for double-sided projection cylindrical part 4 Outer peripheral side flat part 5 Raised part 6 Bottomed cylindrical part 7 Tapered crushing part 8 Bottom hole 9 Preliminary cylindrical part 9a Outer tapered part 9b R-shaped part 9c Projection End inner peripheral portion 10 Reverse-extended bottomed cylindrical portion 10a Outer peripheral edge portion 10b Inner bottom peripheral edge portion 11 Double-sided protruding cylindrical portion 12 Extraction hole 13 Circular flange portion 14 Protrusion 15 Concave hole 16 Long hole 20 Double-sided protruding cylindrical portion integrated molding Product 31 Sun gear 31a Teeth 32 Bearing 33 External gear 33a Internal tooth 34 Rotor 40 Rotating shaft

Claims (6)

A double-sided projecting cylindrical part molding method from a flat plate that integrally processes a projecting cylindrical part projecting on both sides by processing a flat plate material,
A blank punching process for forming a flat plate blank having a center hole in a circular shape from a flat plate material,
In the central part of the flat plate blank, the molded part for the double-sided protruding cylindrical part that rises in a trapezoidal shape to the one side by the required thickness, the outer peripheral flat part thinner than the thickness of the flat blank in the outer area, the entire outer peripheral edge of the other side A pre-processing press molding process for molding the raised portion;
First, a bottomed cylindrical portion having a predetermined inner diameter projecting to one surface side with respect to the double-sided protruding cylindrical portion molding portion is molded, and a tapered crushing process for securing a wall thickness is performed on the projecting end surface of the bottomed cylindrical portion. Overhang press molding process,
A bottoming press molding process in which a bottomed hole for projecting to the other surface side is provided to the bottomed cylindrical portion subjected to the taper crushing process;
The bottomed cylindrical portion is swelled toward the other side while leaving a predetermined thickness based on the maximum diameter of the tapered crushing portion, and the flat plate blank is passed through the outer tapered portion on one side. A second overhang that integrally projects a preliminarily cylindrical portion that is continuous with one surface, and a reversely bulging bottomed cylindrical portion that is continuous with the other surface of the flat plate blank while the end surface is flat on the other surface side and the outer peripheral edge is rounded. Press molding process;
A re-striking process in which the preliminary cylindrical portion continuously connected to the unit, and a reversely bulging bottomed cylindrical portion are molded into a product size shape to form a double-sided protruding cylindrical portion;
Molding the vent hole of predetermined dimension in a direction opposite bulging bottomed cylindrical portion of the double-sided protruding cylindrical portion became product dimensions, vent holes press-molding the circular flange portion serving as a protruding blind shape on the inner peripheral side molding Process,
A method of forming a double-sided protruding cylindrical part from a flat plate, comprising: A double-sided projecting cylindrical part molding method from a flat plate that integrally processes a projecting cylindrical part projecting on both sides by processing a flat plate material,
A blank punching process for forming a flat plate blank having a center hole in a circular shape from a flat plate material,
In the central part of the flat plate blank, the molded part for the double-sided protruding cylindrical part that rises in a trapezoidal shape to the one side by the required thickness, the outer peripheral flat part thinner than the thickness of the flat blank in the outer area, the entire outer peripheral edge of the other side A pre-processing press molding process for molding the raised portion;
First, a bottomed cylindrical portion having a predetermined inner diameter projecting to one surface side with respect to the double-sided protruding cylindrical portion molding portion is molded, and a tapered crushing process for securing a wall thickness is performed on the projecting end surface of the bottomed cylindrical portion. Overhang press molding process,
A bottoming press molding process in which a bottomed hole for projecting to the other surface side is provided to the bottomed cylindrical portion subjected to the taper crushing process;
The bottomed cylindrical portion is swelled toward the other side while leaving a predetermined thickness based on the maximum diameter of the tapered crushing portion, and the flat plate blank is passed through the outer tapered portion on one side. A second overhang that integrally projects a preliminarily cylindrical portion that is continuous with one surface, and a reversely bulging bottomed cylindrical portion that is continuous with the other surface of the flat plate blank while the end surface is flat on the other surface side and the outer peripheral edge is rounded. Press molding process;
A pre-cylindrical part outer press forming step for forming the outer tapered part of the pre-cylindrical part into an R shape;
A first wrist-like process in which the preliminary cylindrical portion that is integrally formed and a reverse-extended bottomed cylindrical portion is formed into a product size shape to form a double-sided protruding cylindrical portion;
A second wrist-like process in which the projecting end inner peripheral portion of the preliminary cylindrical portion and the inner bottom peripheral portion of the reversely bulging bottomed cylindrical portion that are in the product dimension shape are each formed into an R shape;
Molding the vent hole of predetermined dimension in a direction opposite bulging bottomed cylindrical portion of the double-sided protruding cylindrical portion became product dimensions, vent holes press-molding the circular flange portion serving as a protruding blind shape on the inner peripheral side molding Process,
A method of forming a double-sided protruding cylindrical part from a flat plate, comprising: A double-sided projecting cylindrical part molding method from a flat plate that integrally processes a projecting cylindrical part projecting on both sides by processing a flat plate material,
A blank punching process for forming a flat plate blank having a center hole in a circular shape from a flat plate material,
In the central part of the flat plate blank, the molded part for the double-sided protruding cylindrical part that rises in a trapezoidal shape to the one side by the required thickness, the outer peripheral flat part thinner than the thickness of the flat blank in the outer area, the entire outer peripheral edge of the other side A pre-processing press molding process for molding the raised portion;
First, a bottomed cylindrical portion having a predetermined inner diameter projecting to one surface side with respect to the double-sided protruding cylindrical portion molding portion is molded, and a tapered crushing process for securing a wall thickness is performed on the projecting end surface of the bottomed cylindrical portion. Overhang press molding process,
A bottoming press molding process in which a bottomed hole for projecting to the other surface side is provided to the bottomed cylindrical portion subjected to the taper crushing process;
The bottomed cylindrical portion is swelled toward the other side while leaving a predetermined thickness based on the maximum diameter of the tapered crushing portion, and the flat plate blank is passed through the outer tapered portion on one side. A second overhang that integrally projects a preliminarily cylindrical portion that is continuous with one surface, and a reversely bulging bottomed cylindrical portion that is continuous with the other surface of the flat plate blank while the end surface is flat on the other surface side and the outer peripheral edge is rounded. Press molding process;
A pre-cylindrical part outer press forming step for forming the outer tapered part of the pre-cylindrical part into an R shape;
A first wrist-like process in which the preliminary cylindrical portion that is integrally formed and a reverse-extended bottomed cylindrical portion is formed into a product size shape to form a double-sided protruding cylindrical portion;
A second wrist-like process in which the projecting end inner peripheral portion of the preliminary cylindrical portion and the inner bottom peripheral portion of the reversely bulging bottomed cylindrical portion that are in the product dimension shape are each formed into an R shape;
Molding the vent hole of predetermined dimension in a direction opposite bulging bottomed cylindrical portion of the double-sided protruding cylindrical portion became product dimensions, vent holes press-molding the circular flange portion serving as a protruding blind shape on the inner peripheral side molding Process,
A protrusion press molding step for forming a plurality of protrusions in a circular arrangement that protrudes on the outer peripheral side flat portion and protrudes on the other surface side and has a cross-sectional convex concave hole from one surface side therein, and
A method of forming a double-sided protruding cylindrical part from a flat plate, comprising: The center of the circular flat plate, one side, integrally connected to at projecting state to both the other surface, a demarcated been inner circumference side to the protruding blind shape by a circular vent hole in the projecting end portion of the other surface-side circular flange portion A double-sided projecting cylindrical part integrally formed by pressing a double-sided projecting cylindrical part by pressing. The center of the circular flat plate, one side, integrally connected to at projecting state to both the other surface, a demarcated been inner circumference side to the protruding blind shape by a circular vent hole in the projecting end portion of the other surface-side circular flange portion The two-sided projecting cylindrical part with an R-shaped connecting part with the flat plate material on the outer periphery of the one-side projecting part, the inner peripheral end part of the one-side projecting end, and the inner bottom peripheral part of the circular flange part is integrated by pressing. A double-sided protruding cylindrical part integrally molded product characterized by being molded. One side, integrally connected to at projecting state to both the other side, a circular collar which is a bounded been inner circumference side to the protruding blind shape by a circular vent hole in the projecting end portion of the other surface side positioned at the center of the circular flat plate A double-sided projecting cylindrical portion having an R-shaped connecting portion with a flat plate material on the outer periphery of the one-surface-side protruding portion, an inner peripheral end portion of the one-surface-side protruding end, and an inner bottom peripheral edge portion of the circular flange portion, and the flat plate A double-sided projecting cylindrical part integrated with a plurality of circularly arranged projections projecting to the other side in the region of the material and having a concave hole with a cross-sectional convex shape from one side inside thereof by press working Molding.

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