JPS617022A - Method of forming bottomed cylindrical body made of metal - Google Patents

Abstract

PURPOSE:To make radius of shoulder part of an upset formed body to a designated specific value or less when a metallic bottomed cylindrical semi-forming body is fitted to the outside of a columnar core box and inserted into a columnar outer die, by making the gap from the bottom of the columnar core box to specific coefficient relation for radius of shoulder of circular outer edge of the semi-formed body. CONSTITUTION:The metallic bottomed cylindrical semi-formed body 3 made by pressing a discoid blank is fitted to the outside of the columnar core box 4 closely contacting the body, and inserted into the cylindrical outer die 2 closely contacting the body. In this case, the gap DELTAh between the bottom face of the columnar core box 4 and bottom face in the semi-formed body 3 with respect to the radius R0 of shoulder part of circular outer edge of the semi-formed body 3 is made to relation expressed by the formula I and upset by a punch 1. The radius R of the shoulder part of the circular outer edge of the upset formed body 10 becomes a designated value of less than 2mm.. Mass production is possible compared with conventional cold forging and grinding work.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a metal cylinder with a bottom, which is a relatively small product, by pressing.

[Conventional technology]

A metal cylinder with a bottom, which is a relatively small product, is used, for example, for automobile disc brakes.

In other words, the newly edited Automobile Engineering Handbook (issued May 25, 1981) edited by the Tsuji Association of Automobile Engineers, Volume 6; For disc brakes.

A cylindrical body with a bottom is used as the piston.

The outline of this bottomed cylindrical body will be explained with reference to FIG. 9+11 t2+'.

In Fig. 9 (1), t10+ is a cylindrical body with a bottom, and a bottom part - is connected to one end of one cylindrical part (ll) via a shoulder part A, and the outer peripheral edge of the shoulder part A is rounded. have

The one shown in FIG. 9(2) differs from FIG. 9+11 in that a coining processing part α4 is applied to the bottom part, but the other points are the same.

When using this cylindrical body 1101'Th as a piston, it is necessary that the outer circumferential surface be plated and that there be no burrs at each corner. In order to prevent scratches and ensure sealing performance, it is especially necessary to maintain the correct shape of the shoulder part.

Therefore, conventionally, one cylindrical body 1101. In other words, when manufacturing pistons, they are cold forged.

The outer peripheral surface of the cylindrical part (111 and the bottom!
t.

[Problem that the invention seeks to solve]

The conventional manufacturing method using cold forging, grinding, etc. ff1-
t'H, filAlthough it is possible to manufacture a cylinder with a sharp shape, it has the problem of poor productivity and difficulty in adapting to mass production.Especially since it is a small product, It's bad for productivity.

The present invention improves productivity while producing a sharp shoulder part by press forming the cylindrical body which has conventionally been produced by cold forging, grinding, etc. [Means for solving the problem] In the present invention, for example, a circular plate-shaped plastic material suitable for drawing is sheared from a hot-rolled mild steel plate. Then, this rL is molded into a press mold at least once and subjected to drawing processing to create a cylindrical semi-molded body having a body and a bottom, and this semi-molded body is made up of a core mold and an outer mold. The round shape of the shoulder part is created by charging the press mold, creating a desired gap between the top of the core mold and the inner surface of the bottom mold of the semi-formed body, and upsetting it with a punch in its original state. A sharp cylindrical body with a bottom is formed.

〔Example〕

@The configuration of the present invention with reference to the drawings shown in Figures 1 to 8,
Examples will be explained step by step.

Figure W41 shows a press die used for upsetting, which includes a core die (4), an outer die (2) that is fitted into the core die (4) and fitted onto the sleeve, and a punch 11). Base (6)
It is mainly composed of the core mold (4) and the molding part of the outer part of the trunk and the inner peripheral part of the bottom. The outer mold (2) is cylindrical and has a molded portion on the inner circumference of the body.

Then, a cylindrical semi-molded body (3) having a body part (3B) and a bottom part (3B) is set between the core mold 141 and the outer mold (2), and at this time, the core mold (4 There is a desired gap (upset amount) indicated by Δh between the molded part of the bottom inner circumferential surface of the semi-molded body (3) and the bottom inner surface of the semi-molded body (3).

Therefore, the above-mentioned cylindrical semi-molded body (3) has a standard 8
From hot rolled mild steel plates such as PHC-P and 5PHD-P.

As shown in FIG. 2, a circular plate-shaped blank material (6) is blanked and then drawn using a press die.

In addition, during blanking, it is necessary to control the finished state of the sheared surface. This is because it leads to non-uniform deformation of the edge after the drawing process in the first step.

This blank material (6) is subjected to at least one drawing process to produce a cylindrical semi-formed body (3) having a trunk 1 full (3A) and a bottom (3B).

Figure 3 shows the first drawing process of the frame, at this time R
1 is desirably at least twice as large as C due to the plate thickness. This process is performed to make R1 thicker (drawing having an outer diameter D1 using an L7t punch) in order to reduce the stress caused by the next deep drawing process, that is, to prevent stress concentration.

Fig. 4 shows an example in which deep drawing is further performed with an outer diameter of 1, and the outer diameter of D1 in the first drawing process is further reduced to a diameter of D! It is advantageous for the body to be long and deep-drawn, in which case the s RM is not too small.

That is, R1 is set to be small in consideration of reducing strain on the punch shoulder and ease of upsetting during the next upsetting.

Even if it is nK, the drawing process is applied at least once,
Shoulder' in the cross section of the bottom outer periphery as shown in Figure 5 (1)
A cylindrical semi-formed body (3) having a body part (3A) and a bottom part (3B) with a radius of Ro is created by drawing.

The first cylindrical semi-formed body (3) is processed to fit into this machining machine.
As shown in the figure, the nine press molds are set with a gap Δhff:, and the punch (1) is used to upset a bottomed cylindrical body (XO) having a roundness Ri as shown in Figure 5 (2). be.

In this upsetting process, the correlation between Δ:・ and the ribs is as follows:
−0,75).

This correlation will be explained based on FIG. 6, and the experimental conditions used to find this relationship will be explained.

Experimental conditions Material: 5FHO-P Plate thickness: 4.5 cod t Press process (a) Blanking: 100 cod y (b) Drawing process: D = 50 m + 0 (see Fig. 1) Forming height h (Fig. 1 Reference) h≧40 cod (unified to 40 cod) Rib = 7.0 to 20.0 (5 gardens are the standard) (next leaf) Table 1 That is, the above experimental conditions and the scope of the present invention, Δh
= (0,43Ro-0,86)~(0,5Ro-0,
75)! 7) Within the range, R= as the roundness of the shoulder ■
It is also clear from the notes in Table 1 that it is in the range of 1.5 to 2.0.

Upsetting is performed using the press mold shown in Fig. 1 by flowing the material of the punch head from the punch shoulder in a radial outward direction, but at this time, the core m(4) and the outer mold The torso (3A) is restrained by (2).

In this way, it is advantageous to reduce the punch load by changing the cross-sectional shape of the bottomed cylindrical body shown in FIG. 9(1) by upsetting the material movement caused by coining.

In addition to the above-mentioned upsetting process, as shown in FIG.
A cylindrical body with a bottom as shown in Figure (2) can also be formed.

Further, as shown in FIG. 8, it is effective to provide a draft angle θ in order to remove the molded product after upsetting.

Furthermore, ironing can be applied to correct taper and shape defects in the walls of the molded product, the pick, and the cylindrical body σQ.

In this case, the ironing rate is several percent or less, for example, the wall thickness is 0.2
The more W you reduce, the better.

Further, in the case where the cylindrical body αQ is the aforementioned brake piston, the outer circumferential surface is plated or the like in the conventional manner.

Example 1 A blank material (6) was prepared by shearing an 8PHC-P hot-rolled mild steel plate (thickness: 4.5 mm) into a diameter of 75 M0 for one rank, with a drawing outer diameter of 55 mm and a forming height of h. :18 Cod,)Lo: 8
A semi-molded body (3) of sm was produced by one drawing process.

Set this in a press mold, and Δh (swaging amount) is 5.
．． When the cod was swaged and processed, a bottomed cylindrical body with a sharply rounded shoulder with a diameter of 1.8 mm was formed.

Example 2 8PHD-P hot-rolled mild steel plate (thickness 3.2m+) is sheared to a lab blank diameter of 123fi* to obtain a blank material (6), which has a throttle outer diameter of 75smJ1%Ro 20tm1 Perform the second drawing process, then draw the outer diameter 56f
A second deep drawing process was performed on iO% ribs 14 cod with a forming height of 1161 m, and the swaging amount Δh of this semi-formed body was 6.0.
Set it in a press mold as m, 'fL=1.6mg
A cylindrical body with a bottom was formed by swaging into a shape with .

<Effects of the Invention> In manufacturing a bottomed cylindrical body, the present invention is produced by blanking work, drawing work, and upsetting work from a plate material, so that the conventional cold forging and grinding work are not required. It can be made more suitable for mass production than those made by et al.

In addition, when upsetting a semi-formed body with a bottom, the shoulder radius of the semi-formed body and the amount of upsetting (gear Y/7'
) (Δh) K between (7) and (7) Δh=(0,45R
O-0,86) ~ The shape of the outer peripheral edge of the cylindrical body can be made sharp.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the upsetting press mold according to the present invention;
Fig. 2 is a front view of the blank, Fig. 5 is a sectional view of the semi-formed product obtained by the first drawing process, Fig. 4 is a sectional view of the semi-formed product obtained by the second stage drawing process, and Fig. 5 (13( 2) is a partial sectional view showing the shape after drawing and upsetting, FIG. 6 is a graph showing the correlation between the outer radius of the semi-formed body and the swaging amount Δh, and FIG. A sectional view of another example, FIG. 8 is a partial sectional view of a press mold having a draft angle, FIG. 9 (1) (
21 is a sectional view showing two examples of a bottomed cylindrical body. (1)...Punch, (2)...Cylindrical outer mold, (3)
... Semi-molded body, (4) ... Core mold, (Δh) ...
Gap (upsetting amount), (6)...Blank material, α
Q: Cylindrical body, ■: Shoulder.

Claims (1)

[Claims] 1. A circular flat plate blank material (6) is subjected to at least one drawing process by pressing to form a body part (3A) and a bottom part (3B), and then the drawn cylinder The shaped semi-molded body (3) is formed into a core mold (4) having a molded part of an inner circumferential surface of the body and an inner circumferential surface of the bottom, and an outer circumference of the body which is molded and fitted into the core mold (4). and a cylindrical outer mold (2) having a molding part of
) by upsetting the bottom (3B) of the shoulder (12
) is a molding method for a metal bottomed cylindrical body (10) in which the radius R of the outer peripheral edge is 2.0 mm or less, wherein the body (3A) of the semi-molded body (3) is a core mold (4). is set between the body inner peripheral surface molding part of the outer mold (2) and the trunk outer peripheral molding part of the outer mold (2), and in this set state, the bottom inner peripheral surface of the semi-molded body (3) and the bottom part of the core mold (4) When there is a desired gap Δh between the inner circumferential surface molded part and the shoulder radius in the cross section of the bottom outer periphery of the semi-molded body (3) is R_0, the gap Δh is calculated as follows: Δh=(0.43R_0 -0.86) ~ (0.5R_0
-0.75) A method for forming a metal cylinder with a bottom, characterized by upsetting with a punch (1).