JPH08272B2 - Manufacturing method of sheet metal rotating member - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a method for manufacturing a sheet metal rotating component, such as a rotor for an electromagnetic clutch or the inner ring of a V-pulley, in which a cylindrical boss portion for fitting onto the outside of a rotating body such as a rotating shaft is formed integrally at the center of a plate-like metal material, protruding to one side, and a cylindrical peripheral wall portion for fixed connection to the outer ring is formed integrally at the outer periphery of the sheet metal material, protruding concentrically in the same direction as the boss portion; or a sheet metal rotating component, such as an intermediate part of a sheet metal V-pulley or sheet metal poly V-pulley, in which only a cylindrical boss portion for fitting onto the outside of a rotating body such as a rotating shaft is formed integrally at the center of the plate-like metal material, protruding to one side.

BACKGROUND ART A method for manufacturing a predetermined rotating member by forming only a cylindrical boss portion that protrudes to one side from the center of a plate-shaped metal material,
Alternatively, a conventional method for manufacturing a predetermined rotating member by forming a cylindrical boss portion protruding to one side at the center of a plate-shaped metal material and forming a cylindrical peripheral wall portion protruding concentrically in the same direction as the boss portion on the outer periphery thereof is as follows:
Cold forging is widely used.

However, with the above-mentioned conventional cold forging method, the cylindrical boss portion and cylindrical peripheral wall portion are formed by the plastic flow of the material itself. Therefore, in order to ensure sufficient product strength, a thick material is used, and in sheet metal products such as electromagnetic clutch rotors and sheet metal V-pulleys, which require a boss portion with a relatively small diameter and a relatively large protrusion (height), or sheet metal products which require the formation of a relatively narrow annular space between the boss portion and the peripheral wall portion which are positioned concentrically inside and outside, it is difficult to form a boss portion with a specified diameter and protrusion height, or to form a narrow annular space, even if a large press of the 2000 to 2500 ton class is used. Therefore, there is a problem that the range of workability is naturally limited by the relationship between dimensions such as diameter and height and plate thickness.

The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a method for manufacturing a rotating member made of sheet metal that can accurately form boss portions and boss portion and peripheral wall portions of the desired diameter, thickness, and height using a small press without making the plate thickness too thin.

Disclosure of the Invention In order to achieve the above-mentioned object, the manufacturing method of a sheet metal rotating member according to the present invention is a manufacturing method of a sheet metal rotating member in which a cylindrical boss portion that protrudes toward one side of a plate-shaped metal material is formed in the center of the material, and includes a bending process in which the metal material is bent convexly toward the protruding side of the boss portion, and a multi-stage bending process in which the curved portion is bent multiple times in the direction opposite to the bending direction so as to gradually reduce its diameter, while restricting the radially outward expansion of the outer peripheral edge portion of the curved material to prevent the material from escaping radially outward, to form a bottomed cylindrical boss portion and an annular flat portion.

According to the method for manufacturing a sheet metal rotary member of the present invention, the process of curving the metal blank to form the cylindrical boss and the process of bending the curved portion in multiple stages are both types of bending, which prevents a decrease in sheet thickness due to plastic flow of the material and a resulting decrease in strength, and allows the desired boss portion to be easily formed using a relatively small press, even for a metal blank with a considerable thickness. Moreover, during the bending process, the material is bent multiple times to gradually reduce its diameter while restricting the radial outward expansion of the outer peripheral edge of the blank to prevent outward escape of the blank, thereby causing the blank to flow primarily toward the center, i.e., toward the boss portion to be formed, and thereby allowing the formation of a boss portion with sufficient thickness and protruding height, even for a small inner diameter.

Furthermore, in the manufacturing method of a sheet metal rotating member according to the present invention, a cylindrical boss portion that protrudes toward one side of a plate-shaped metal material is formed at the center of the material, and a cylindrical peripheral wall portion that protrudes concentrically in the same direction as the boss portion is formed on the outer periphery of the plate-shaped metal material, the manufacturing method of a sheet metal rotating member includes the following steps: a first bending step in which the metal material is curved convexly toward the protruding side of the boss portion; a multi-stage bending step in which, while restricting the radially outward expansion of the outer periphery of the curved material to prevent the material from escaping radially outward, the curved portion is bent a plurality of times in the direction opposite to the bending direction so as to gradually reduce its diameter, to form a bottomed cylindrical boss portion and an annular flat portion; and a second bending step in which, while restricting deformation of the bottomed cylindrical boss portion of the material after the multi-stage bending step, an outer semi-circumferential portion of the annular flat portion is bent in the direction opposite to the boss portion to form a raised cylindrical peripheral wall portion.

According to the method for manufacturing a sheet metal rotary member of the present invention, a first metal blank for forming a cylindrical boss portion is
The bending step, the multiple bending steps for the curved portion, and the second bending step for the flat portion for forming the cylindrical peripheral wall portion are all types of bending processes.
This method can suppress the reduction in plate thickness due to the plastic flow of the material and the resulting decrease in strength, and can easily form the desired boss and peripheral wall portions using a relatively small press, even when the plate thickness is a fairly thick metal material. Moreover, during the bending process, the material is bent multiple times so as to gradually reduce the diameter while restricting the radial outward expansion of the outer peripheral edge of the material to prevent the material from escaping outward, and the material is caused to flow mainly toward the center, i.e., toward the boss portion to be formed, so that a boss portion with sufficient thickness and protruding height can be formed even when the inner diameter is small.
During the bending process, by restricting the deformation of the boss portion formed in the multiple bending process, the escape (flow) of the material in both directions is prevented, and not only is the deformation of the boss portion prevented,
A peripheral wall portion with sufficient thickness can be formed. Furthermore, by restricting the radial outward expansion of the outer peripheral edge portion and restricting deformation of the boss portion, the dimensional accuracy of the entire joint can be improved.

Furthermore, after the multiple bending steps, a finishing step is provided in which the bottom of the bottomed cylindrical boss formed in the bending steps is compressed from the axial direction so that it protrudes to a predetermined height and is flat. This improves the finishing precision of the boss with the predetermined protruding height, and the portion that protrudes excessively in the height direction contributes to thickening the boss, which is even more effective in terms of strength of the boss.

Furthermore, after the second bending process, a cutting process is performed in which the protruding end portion of the bottomed cylindrical boss portion formed in the bending process is cut at a predetermined protruding height to form a shaft insertion hole.This makes it possible to absorb any errors in dimensional accuracy that may occur in the bending process or multiple bending processes, and ultimately obtain a rotating member with extremely high dimensional accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1A and 1B are cross-sectional views of the main part for explaining the first step of the first bending (drawing) step in the manufacturing method of a sheet metal rotary member according to the present invention.

2A and 2B are cross-sectional views of the main part for explaining the second step of the first bending (drawing) step.

3A and 3B are cross-sectional views of the main part for explaining the first bending (ironing) step.

4A and 4B are cross-sectional views of the main part for explaining the second bending (ironing) step.

5A and 5B are cross-sectional views of the main part for explaining the third bending (ironing) step.

6A and 6B are cross-sectional views of the main part for explaining the fourth bending (ironing) step.

7A and 7B are cross-sectional views of the main part for explaining the second bending (drawing) step.

8A and 8B are a longitudinal sectional view and a plan view of the manufactured sheet metal rotating member.

Fig. 9 is a vertical cross-sectional view of the manufactured sheet metal rotating member incorporated as the rotor of an electromagnetic clutch.

Fig. 10 is a vertical cross-sectional view of the manufactured sheet metal rotating member incorporated as the inner ring of a V-pulley.

FIG. 11 is a vertical cross-sectional view of a product manufactured by another method for manufacturing a sheet metal rotating member according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION First, among the embodiments of the manufacturing method of a sheet metal rotating member according to the present invention, an embodiment of a manufacturing method of a rotor to be incorporated and used in an electromagnetic clutch will be described with reference to the drawings. In this embodiment, a circular metal plate material with a plate thickness t of about 3 to 5 mm is used, and the inner diameter d1 of the boss portion is about 60 mm.
The outer diameter d2 of the peripheral wall is about 120 to 150 mm, and the protruding height of the boss is h
The case of forming a rotor for an electromagnetic clutch having a diameter of about 28 to 32 mm will be described.

In the first step of the first bending (drawing) process, as shown in FIG. 1A, a circular, flat metal blank 1 is set on a lower die 2 consisting of a punch 2a and a punch holder 2b, and then:
The upper die 3 is made up of the lower die 2, the die 3a and the die holder 3b.
By bringing these two parts close to each other using a press (not shown), the metal blank 1 is curved into a two-stage convex shape as a whole toward the protruding side of the boss portion, as shown in Fig. 1B. The curved shape at this time is determined by the tip shape of the punch 2a of the lower die 2 and the tapered entrance surface of the die holder 3b of the upper die 3.
Determined by the shape of 3b1.

In the second step of the first bending (drawing) process, as shown in Figs. 2A and 2B, punches 2a with different tip shapes and die holders 3b with different entrance tapered surface 3b1 shapes are interchangeably used, and the upper die 3 and the lower die 2 are brought close to each other in the same manner as above, thereby drawing the blank 1 into a substantially conical shape overall.

Next, bending (ironing) is performed to form the cylindrical boss portion.
This bending process is shown in Fig.3.
As shown in Figs. 3A, 3B, 6A, and 6B, the first to fourth steps are divided into multiple steps, and the lower die of a die dedicated to ironing, which is different from the die used in the first bending (drawing) step, is used.
The protrusion amount and tip curvature of the punch 12a of 12, and
By sequentially replacing and using the inlet corner 13b2 of the die holder 13b of the upper die 13 with different curvatures, the upper die 13 and the lower die 12 are brought close to each other, so that the curved portion 1b is ironed and bent multiple times in the direction opposite to the bending direction and so that the diameter is gradually reduced.
1b is deformed along the outer peripheral surface of the punch 12a to form a cylindrical boss portion 6 with a bottom at the center, and an annular flat portion 5 is formed on the outer periphery thereof.

Of the above-mentioned multi-stage bending processes, Fig. 6A and
In the fourth step shown in Fig. 6B, a punch 12a2 is used exclusively for finishing.
A boss finishing process is carried out in which the bottom 6a of the cylindrical boss portion 6 is compressed in the axial direction using the die holder 13b2, thereby finishing the bottom 6a of the cylindrical boss portion 6 to a predetermined protruding height and to make it flat.

In the multi-stage bending process described above, the outer peripheral edge 1e of the blank 1 abuts against the inner surface of the protrusion 12c formed in an annular shape on the punch holder 12b of the lower die 12, and radial outward expansion is constantly restricted. This prevents the material of the blank 1 from escaping radially outward, and instead causes it to escape toward the cylindrical boss portion 6, making it possible to ensure that the wall thickness and the length of the straight portion of the cylindrical boss portion 6 are sufficiently large.

Next, a peripheral wall portion concentric with the cylindrical boss portion 6 is formed on the blank 1.
As shown in Fig. 7A, the second bending (drawing) process is performed to form a cylindrical boss portion 6 having an outer diameter approximately equal to the inner diameter of the cylindrical boss portion 6.
The blank 1 on which the cylindrical boss portion 6 and the annular flat portion 5 are formed as described above is set on a lower mold 22 having a central protrusion 22a with a flat upper end surface and an annular movable portion 22b slidably fitted and held on the central protrusion 22a. Then, the upper mold 23 and the lower mold 22 are brought close to each other by a press, and the upper mold 23 is composed of a cylindrical protrusion 23a having an inner diameter substantially equal to the outer diameter of the cylindrical boss portion 6 and a wall thickness of about half the radial width of the annular flat portion 5, and a columnar portion 23b fitted and fixed within the cylindrical protrusion 23a so that its tip surface is located at a position recessed from the tip of the cylindrical protrusion 23a by a distance corresponding to the protrusion height of the cylindrical boss portion 6, as shown in FIG. 7B.
While restricting deformation of the boss portion 6 by inserting the central protrusion 22a of the lower die 22 into the cavity in a tight contact state, the outer half of the annular flat portion 5 is curved in the opposite direction to the boss portion 6, and a cylindrical peripheral wall portion 7 is formed on the outer periphery thereof, protruding in the same direction as the boss portion 6. In this second curving step, deformation of the cylindrical boss portion 6 is restricted by the insertion of the central protrusion 22a of the lower die 22 into the cavity, so that the escape (flow) of the material in both the inward and outward directions is prevented.
This not only prevents the boss portion 6 from being deformed, but also allows the peripheral wall portion 7 to be formed with a sufficient thickness.

After the above steps are completed, the protruding end portion including the bottom portion 6a of the bottomed cylindrical boss portion 6 is cut to a predetermined protruding height h to form the shaft insertion hole 8, as shown in Figs. 8A and 8B.
As shown in FIG. 8B, an electromagnetic clutch rotor R having the dimensions of each part as described above is manufactured.

As shown in Fig. 9, the rotor R manufactured as described above is used to form a predetermined electromagnetic clutch by inserting a rotating shaft 11 rotatably into the shaft insertion hole 8 at the center of the cylindrical boss portion 6 via a bearing 10, incorporating an electromagnetic clutch core 15 into the annular space 14 formed between the boss portion 6 and the peripheral wall portion 7 and open in one direction, fixing a rotation transmission ring 17 such as a poly V-pulley to the outer periphery of the peripheral wall portion 7 with bolts 16, and further arranging an armature 18 that rotates integrally with the rotating shaft 11 on the outer surface of the flat portion 5 of the rotor R.

When the rotor is used as an electromagnetic clutch rotor as described above, it is preferable to form arc-shaped heat dissipation holes 19 in the flat portion 5 as shown in Fig. 8 in order to improve heat dissipation from the annular space 14 in which the core 15 is installed.

In the above embodiment, a method for manufacturing a sheet metal rotary member used as a rotor for an electromagnetic clutch has been described, but the use is not limited to this. For example,
As shown in FIG. 10, the present invention may be applied to the manufacture of a rotating member used as the inner ring of a V-pulley 19.

FIG. 11 is a longitudinal sectional view of an intermediate part of a sheet metal V-pulley or a sheet metal poly V-pulley manufactured by the method for manufacturing a sheet metal rotating member according to the present invention.
is manufactured by going through the same steps as those shown in Figs. 1A and 1B to 6A and 6B described above, forming a bottomed cylindrical boss portion 6 in the center and an annular flat portion 5 on its outer periphery, and then cutting the protruding end portion including the bottom portion 6a of the bottomed cylindrical boss portion 6 to a predetermined protruding height h, or by punching out the bottom portion 6a, forming a shaft insertion hole 8 in the center.

INDUSTRIAL APPLICABILITY As described above, the method for manufacturing a sheet metal rotating member of the present invention is a method for manufacturing a sheet metal rotating member by integrally forming only a cylindrical boss portion that protrudes toward one side at the center of a plate-shaped metal material, or
This technology is used to integrally form the cylindrical boss and to form a cylindrical peripheral wall that protrudes concentrically in the same direction as the boss from the outer periphery of the metal plate material. By combining a type of bending process, it is possible to accurately form the boss or the boss and peripheral wall with the desired diameter, thickness, and height without making the plate too thin, and using a small press. This manufacturing technology can be effectively used in the manufacture of electromagnetic clutch rotors, sheet metal V-pulleys, etc.

Claims (6)

[Claims] [Claim 1] A method for manufacturing a sheet metal rotating member, in which a cylindrical boss portion that protrudes toward one side of a plate-shaped metal material is formed at the center of the material, comprising: a bending process for curving the metal material convexly toward the protruding side of the boss portion; and a multi-stage bending process for bending the curved portion multiple times in the direction opposite to the bending direction so as to gradually reduce the diameter, while restricting the radial outward expansion of the outer peripheral edge portion of the curved material to prevent radial outward escape of the material, to form a bottomed cylindrical boss portion and an annular flat portion. [Claim 2] A method for manufacturing a sheet metal rotating member, in which a cylindrical boss portion is formed at the center of a plate-shaped metal material, protruding toward one side of the material, and a cylindrical peripheral wall portion is formed on the outer periphery of the plate-shaped metal material, protruding concentrically in the same direction as the boss portion, the method comprising: a first bending process, in which the metal material is curved convexly toward the protruding side of the boss portion; a multi-stage bending process, in which the curved portion is bent a plurality of times in the direction opposite to the bending direction and so as to gradually reduce its diameter, to form a bottomed cylindrical boss portion and an annular flat portion, while restricting the radially outward expansion of the outer peripheral edge portion of the curved material to prevent radially outward escape of the material; and a second bending process, in which the outer semi-circumferential portion of the annular flat portion is curved convexly in the direction opposite to the boss portion, to form the cylindrical peripheral wall portion, while restricting deformation of the bottomed cylindrical boss portion of the material after the multi-stage bending process. [Claim 3] A method for manufacturing a sheet metal rotating member as described in claim 1, which includes a finishing process after the multiple-stage bending process, in which the bottom of the bottomed cylindrical boss portion formed in the bending process is compressed from the axial direction so that it protrudes to a predetermined height and is flat. [Claim 4] A method for manufacturing a sheet metal rotating member as described in claim 2, which includes a finishing process after the multiple-stage bending process, in which the bottom of the bottomed cylindrical boss portion formed in the bending process is compressed from the axial direction so that it has a predetermined protruding height and is flat. [Claim 5] A method for manufacturing a sheet metal rotating member as described in claim 2, which includes a cutting process after the second bending process, in which the protruding end portion of the bottomed cylindrical boss portion formed in the bending process is cut at a predetermined protruding height position to form an axis insertion hole. [Claim 6] A method for manufacturing a sheet metal rotating member as described in claim 3, which includes a cutting process after the second bending process, in which the protruding end portion of the bottomed cylindrical boss portion formed in the bending process is cut at a predetermined protruding height position to form an axis insertion hole.