JP2002239651A - Sheet metal with boss and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce manufacturing cost and weight of a sheet metal by forming a tubular boss part, which has a desired bore, thickness and height as well as a satisfactory strength, integrally with the sheet metal by using a small press. SOLUTION: A plurality of notches 4a are radially formed on the outer circumference of a planar metallic base material 4, with drawing performed on this notched material 4 to form a bulged part 5a. Then, a post processing is applied to this bulged part 5a to form the boss part 3a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boss-formed sheet metal formed by forming a boss by drawing a flat metal material. Here, the sheet metal member is, for example, a metal core metal having a cylindrical boss for fitting a rotating shaft used for a resin gear, or a pulley having a cylindrical boss for fitting a rotating shaft.

[0002]

2. Description of the Related Art In a resin gear provided with a metal core having a boss fitted to a rotating shaft, for example, as shown in FIG.
The resin gear 1 is formed by injection molding a resin portion 2 having a tooth-shaped portion 2a on one side surface and an outer peripheral surface of a metal core 3 having a cylindrical boss portion 3a.

[0003] In this case, the force in the rotating direction is the metal core 3
And the axial force is received by molding the resin so as to sandwich the flange outer cylindrical portion 3d of the cored bar 3 from both sides. .

Further, a rotary shaft (not shown) is press-fitted into the cylindrical boss portion 3a, but the boss portion 3a has a sufficient length in the axial direction in order to increase the coupling force by this press-fitting. In some cases, it is necessary to have a sufficient thickness in the radial direction.

In order to satisfy such strength conditions,
When manufacturing the metal core 3 integrally provided with the cylindrical boss 3a, the boss 3a is formed by cold forging,
The shape is adjusted by cutting.

[0006]

However, when the boss is formed by cold forging, the weight cannot be reduced, the number of steps is large, and large-scale special equipment is required.
However, there is a limit to the reduction of the manufacturing cost.

For this reason, there is a method of integrally forming a cylindrical boss from a sheet metal by burring. However, in the case of burring, a hole is formed in a flat portion with a punch or the like, and the flat portion around the hole is raised while expanding the hole, so that a cylindrical boss having a high height is formed. If an attempt is made to obtain, the inner diameter of the boss portion will also increase. That is, assuming that the height of the boss is h and the radius of the inner diameter of the boss is r, only the boss with h <r can be formed. Further, since the thickness of the boss is smaller than the thickness t0 of the material, it may be difficult to manufacture a boss having sufficient strength from a sheet metal.

There is also a method of integrally forming a cylindrical boss from a sheet metal by drawing. However, in the case of drawing, there is a certain restriction on the relationship between the diameter of the metal material and the diameter of the drawn portion, and the thickness of the boss portion tends to be reduced, and satisfactory strength cannot be obtained. There is. In particular, as shown in FIG. 6, in the case of a combination in which the outer diameter is large and the diameter of the boss portion 3a is small, even when the drawing is performed, the diameter of the outer diameter portion is hardly reduced because the strength of the material is high. The aperture of
The outer diameter portion of the material is pulled inward by the drawing action and is reduced in diameter, and the drawing in the inner portion progresses accordingly.), And the volume of the plastic flow becomes insufficient, and it is difficult to obtain a desired shape. And so on.

The present invention has been made in view of the above circumstances, and has a desired inner diameter, wall thickness, and height.
Provided is a sheet metal product with a boss portion, which can integrally form a cylindrical boss portion having satisfactory strength by using a small press to reduce manufacturing costs and reduce the weight of the sheet metal product, and a method of manufacturing the same. The purpose is to do.

[0010]

In order to achieve the above object, a first object of the present invention is to provide a metal plate with a boss having a boss, wherein a plurality of diameters are provided on an outer peripheral portion of a flat metal material. Boss formed by forming a notch in the direction, drawing the material with the notch to form a bulging portion, and then performing a post-process on the bulging portion to form a boss portion. It is a sheet metal part with a part.

A second aspect of the present invention is characterized in that the plurality of radial notches formed in the outer peripheral portion of the material are set in advance so that the notched end faces are substantially in close contact with each other after drawing is completed. The metal plate with a boss according to claim 1.

In a third aspect of the present invention, there is provided a method of manufacturing a boss-equipped sheet metal having a boss, wherein a plurality of radial notches are formed in an outer peripheral portion of the flat metal material, and the notch is formed. A method for producing a bossed sheet metal product, comprising drawing a swelling portion of a material with a swelling portion to form a swelling portion, and then performing a post-process on the swelling portion to form a boss portion.

Further, a plurality of radial cutouts formed in the outer peripheral portion of the material are set in advance so that the cutout end faces are substantially in close contact with each other after the drawing process is completed. The method of manufacturing a metal plate with a boss according to claim 3.

[0014] Further, the radial length of the plurality of notches formed in the outer peripheral portion of the material is preferably 1/3 of the radius of the material.
The method according to claim 3, wherein the metal member has a boss.

As described above, according to the present invention, since the material having the notch formed in the outer peripheral portion is drawn, the resistance when the material is reduced in diameter due to the notch disappears, so that the material can be easily contracted. Diameter and drawing can be performed smoothly. For this reason, the volume of the squeezed portion increases, and the shape of the boss portion is easily formed. Therefore, a product in which the axial length and thickness of the boss portion are sufficiently ensured can be produced from the sheet metal. In addition, the notch of the material is easily joined by drawing to form a streak, so that there is no inconvenience when used as a final product. Although the metal flow is decomposed in the streak portion, it does not reach the boss portion, so there is almost no problem in strength. That is, if the strength of the boss portion is sufficient, there is no problem because the stress acting on the vicinity of the streak portion is small. In the case of a metal core of a resin gear,
Since the streak portion is used by being covered with resin, there is no problem in product function.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a metal plate having a boss according to an embodiment of the present invention;

FIG. 1 is a view showing a material used in a manufacturing method according to an embodiment of the present invention.
(B) is a sectional view of (a). 2A and 2B are diagrams illustrating a first processing step of the manufacturing method according to the embodiment of the present invention, wherein FIG. 2A is a plan view and FIG. 2B is a cross-sectional view of FIG.
FIG. 3 is a cross-sectional view showing second to fifth processing steps of the manufacturing method according to the embodiment of the present invention.
(B) shows the third step, (c) shows the fourth step, and (d) shows the fifth step. FIG. 4 is a diagram showing a metal core bar completed based on the manufacturing method according to the embodiment of the present invention.
1 is a plan view, and FIG. 2B is a cross-sectional view of FIG. 5A and 5B are diagrams showing an example of a resin gear completed by injection molding a resin on a metal core based on the manufacturing method according to the embodiment of the present invention, wherein FIG. 5A is a plan view, and FIG. () Shows a sectional view of (a).

In FIG. 1, a flat metal material 4 is
It has a substantially disk shape and has a plurality of (four) radial cutouts 4a on the outer peripheral side. Although the outer peripheral shape 4b is substantially circular, it is not a perfect circle, but is set to be slightly polygonal (square in the figure) in consideration of a post-process.

The depth B of the notch 4a from the outer periphery is
The depth reaches at least 1/3 of the radius R1 of the material 4 (B
> R1 / 3). The thickness t0 is substantially equal to the thickness t of the finished product (see FIGS. 4 and 5).

In FIG. 1, the contour of the notch 4a is
At the time of the next drawing step, the shape is set in advance so that the notch 4a shrinks to form a streak joint 5b (see FIG. 2). Further, the outer peripheral shape 4b is preferably set to have a curvature such that it becomes a perfect circle when the diameter is reduced in the next step. Further, the contour shape, number, depth and the like of the notch 4a are set so as to be optimal according to the shape of the finished product. The shape (depth, width, contour) of the notch 4a may be determined through trial and error by repeatedly performing a drawing process described later.
It may be obtained by analysis.

Using the raw material 4 shown in FIG. 1, as shown in FIG. 2, a drawing process is performed to form a first intermediate body 5. This drawing may be performed by a general press drawing without any special method.

As shown in FIG. 2, a bulging portion 5a is provided at the center position.
Draw processing is performed so that At this time, notch 4a
Is shrunk to leave no gaps and remains streaked as streak joints 5b, and the outer peripheral shape 4b is reduced in diameter by the action of the notch 4a to form a perfect circle (radius, R2) like the outer peripheral shape 5c. become.

Ideally, the streak joints 5b are tightly joined, and the notch shape and drawing conditions are set so that a certain amount of pressure is generated and the joints come into close contact.

In the case of general drawing, that is, when drawing is performed from a simple disk-shaped metal material having no notch, the outer peripheral wall of the material becomes a resistance, and drawing is performed. Even without a diameter reduction. In order to reduce the diameter, the thickness of the outer peripheral part must be increased in principle. However, if the outer diameter of the material is too large, such stress of increasing the thickness does not occur, and the central narrowed part Only the vicinity is deformed and stretched and thinned.

On the other hand, in the drawing process of FIG. 2, since the notch 4a is provided, it works as if the material whose radius of the material 4 is represented by (R1-B) is narrowed. In addition, a sufficient diameter reduction effect can be expected. Due to this effect, the depth C of the bulging portion 5a in FIG. 2B becomes reasonably deep enough, so that the volume of the boss portion does not become insufficient.

The first intermediate body 5 obtained in FIG. 2 is subjected to a series of post-processes shown in FIG. 3 to complete the metal core 3. First, as shown in FIG. 3 (a), the first intermediate body 5 obtained in FIG. 2 is restricked, and the bulging part 5a is deformed to form a bulging part 6a close to a boss shape. 6 is manufactured.

Subsequently, the bulging portion 6a of the second intermediate body 6 is punched to produce a third intermediate body 7 having a fitting hole formed in the bulging portion 6a (FIG. 3B). Subsequently, the flange 7 of the third intermediate body 7
The fourth intermediate body 8 having the flange outer peripheral cylindrical portion 8a is manufactured by squeezing a (FIG. 3C). Finally, serrations 3 are formed on a part of the outer peripheral cylindrical portion 8a of the fourth intermediate body 8 by cold forging.
Simultaneously with molding c, the boss 3a is restriated to adjust the shape while increasing the thickness of the boss 3a, thereby completing the metal core 3 (FIG. 3D). In addition, all of these processing methods from the first intermediate body 5 to the fourth intermediate body 8 can be realized by a normal level press working technique without using a specially advanced technique.

As shown in FIG. 4, the completed metal core 3 has a boss 3a, a flange 3b, a serration 3c, a flange outer cylindrical portion 3d, and the like. As described above, since the boss 3a has a sufficient volume in the drawing process, the axial length and the wall thickness are sufficiently large.

The larger the depth B of the notch 4a in FIG. 1, the greater the effect of drawing in the outer diameter in the drawing step, and the larger the volume of the boss 3a can be set. However, if it is too deep, the streak joint 5b extends to the boss 3a.
And the strength of the boss 3a is weakened. Conversely, when the depth B of the notch 4a is shallow, the effect of drawing in the outer periphery in the drawing step is small, and the boss 3a
Volume cannot be secured. If the depth is too shallow, the aperture is insufficient and the effect of the present invention cannot be expected. Therefore, the notch depth B needs to be at least 1/3 of the outer radius.
It is efficient to set the notch depth to such an extent that the function of the product is not hindered.

The width A of the notch 4a also affects the drawing process. That is, if the notch width is too small, the effect of the notch 4a becomes thin, and the streak joint 5b is joined in the middle of the drawing process, and the drawing after that becomes incomplete, and the boss portion is insufficient. Volume is not pulled in. Conversely, if the cut width is too wide, the notch will remain even after being squeezed, and the streak joint 5b will be open (not in close contact).

Further, according to the present embodiment, streak joints 5b remain in a part of the metal core 3, and the material is divided in this part (the metal flow is cut).
Therefore, the strength is weaker than that of a conventional product which is not divided. However, there is a great merit that processing can be performed from sheet metal even if this defect is subtracted.

Further, the insufficient strength of the streak joint 5b is as follows.
The reinforcement can be achieved by making the stitched joints 5b alternately overlap each other. Further, it can be strengthened by caulking the streak joint 5b. Since these processes can be woven into a series of press processes, a product having substantially few defects can be finished. Of course, it is also possible to join the streak joints 5b by welding.

Further, since the metal core 3 is manufactured from the sheet metal, the weight can be reduced, and the boss 3a and the flange 3
There is no interruption of the flow at the connection with d. Therefore, a light product having excellent functions can be obtained.

The present invention is not limited to the above-described embodiment, but can be variously modified. For example, in this embodiment,
The metal core used for the resin gear has been described as an example. However, the present invention is not limited to this, and a sheet metal having a boss for rotating shaft fitting, such as a pulley, may be used. That is, the present invention can be widely applied to sheet metal products that require the formation of a cylindrical boss.

[0035]

As described above, according to the present invention, a boss-integrated sheet metal having a sufficient axial length and thickness of the boss is easily manufactured from a flat metal material. Therefore, the production cost can be significantly reduced without requiring special equipment, and the weight of the boss-equipped sheet metal can be reduced.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams illustrating materials used in a manufacturing method according to an embodiment of the present invention, wherein FIG. 1A is a plan view and FIG. 1B is a cross-sectional view of FIG.

FIGS. 2A and 2B are diagrams showing a first processing step of the manufacturing method according to the embodiment of the present invention, wherein FIG. 2A is a plan view and FIG. 2B is a sectional view of FIG.

FIGS. 3A and 3B are cross-sectional views showing second to fifth processing steps of the manufacturing method according to the embodiment of the present invention, wherein FIG.
(B) shows the third step, (c) shows the fourth step, and (d) shows the fifth step.

FIG. 4 is a view showing a metal core bar completed based on the manufacturing method according to the embodiment of the present invention, wherein (a) is a plan view,
(B) shows a sectional view of (a).

FIG. 5 is a diagram showing an example of a resin gear completed by injection molding a resin on a metal core bar based on the manufacturing method according to the embodiment of the present invention, wherein FIG. ) Is (a)
FIG.

6A and 6B are diagrams illustrating an example of a resin gear completed by injection molding a resin on a metal core based on a manufacturing method according to a conventional manufacturing method, wherein FIG. 6A is a plan view, and FIG. (A)
FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 resin gear 2 resin portion 2 a tooth shape portion 3 cored bar 3 a boss portion 3 b flange portion 3 c serration 3 d flange outer peripheral cylindrical portion 4 metal material 4 a notch 4 b outer peripheral shape 5 first intermediate body 5 a bulging portion 5 b streak Joint 5c Outer peripheral shape 6 Second intermediate body 6a Swelling part 7 Third intermediate body 7a Flange part 8 Fourth intermediate body 8a Flange outer peripheral cylindrical part t, t0 Plate thickness A Notch width B Notch depth C Swelling Part depth R1, R2 Radius

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B21K 1/30 B21K 1/30 B

Claims (5)

[Claims] 1. A metal plate with a boss having a boss, wherein a plurality of notches in a radial direction are formed on an outer peripheral portion of a flat metal material, and the notched material is subjected to drawing. A boss portion-formed sheet metal product, wherein a bulge portion is formed, and thereafter, the bulge portion is subjected to a post-process to form a boss portion. 2. The method according to claim 1, wherein the plurality of radial cutouts formed in the outer peripheral portion of the material are set in advance so that the cutout end faces are substantially in close contact with each other after drawing is completed. The metal plate with a boss described in the above. 3. A method of manufacturing a boss-equipped sheet metal having a boss, comprising: forming a plurality of radial notches in an outer peripheral portion of a flat metal material; And forming a bulged portion, and then performing a post-process on the bulged portion to form a boss portion. 4. The method according to claim 3, wherein the plurality of radial notches formed in the outer peripheral portion of the material are preset so that the end faces of the notches are substantially in close contact with each other after drawing is completed. 3. The method for producing a metal plate with a boss according to item 1. 5. The boss-equipped sheet metal product according to claim 3, wherein a radial length of the plurality of notches formed in the outer peripheral portion of the material is at least one third of a radius of the material. Production method.