JP2000176558A - Method for press forming of bottomed boss - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for press forming of a bottomed boss capable of integrally forming a bottomed boss having an outer diameter with high precision on a metal plate in only a few stages of processes. SOLUTION: Through a preliminary process to form a projecting part 3a by preliminarily forming a part of a metallic plate (metal plate) 3 in a half punched state, and through a boss forming process, in which, by squeezing the upper wall of the projecting part 3a formed on the metallic plate 3 through the preliminary process with upper and lower punches 48, 62, the material of the upper wall is made to flow into the surrounding wall of a regulated outer diameter and a bottomed boss 3b with a wall of uniform thickness is formed, the bottomed boss 3b is integrally formed into a part of the metallic plate 3. By means of this method, through only two stages of processes of a preliminary process and a boss forming process, the required bottomed boss 3b is efficiently formed in a part of the metallic plate 3. In the boss forming process, the bottomed boss 3b is formed by squeezing of material, so the bottomed boss 3b having a comparatively high height H (up to a level three times as much as the plate thickness T of the metallic plate 3 (H≈3T)) is formed with high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press forming method for integrally forming a bottomed boss on a plate by press working.

[0002]

2. Description of the Related Art For example, in the assembly of precision instrument parts,
As shown in FIG. 10A, a rivet 6, which is a separate component, is used to connect the two members 4, 5, and a retainer pin 8, which is a separate component, is used to position the spring 7 as shown in FIG. Is used.

However, if the rivet 6 and the retainer pin 8 which are separate parts are used, not only the number of parts increases but also the two members 4 and 5 connected by the rivet 6 and the plate material 9 on which the retainer pin 8 is to be mounted need to be drilled. Therefore, there is a problem that many man-hours are required.

Therefore, as shown in FIG.
An attempt has been made to integrally form a boss 5a for caulking and a boss 9a for positioning on the plate 9 as shown in FIG. 11 (b).

[0005]

However, the conventional boss forming method utilizes the elongation of the material, and not only requires many steps but also the elongation of the material is not uniform. The boss was partially damaged due to the occurrence of a thin portion, and the outer diameter could not be maintained with high accuracy while maintaining the height of the boss.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object the purpose of securing a boss height to a plate material in a small number of steps while integrally integrating a bottomed boss having a highly accurate outer diameter. An object of the present invention is to provide a method for press-forming a bottomed boss that can be formed.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a preliminary step of forming a convex portion by preforming a part of a plate material into a half-blanked shape, and forming the convex portion on the plate material by the preliminary step. By crushing the upper wall of the convex portion with upper and lower punches, the material of the upper wall is caused to flow to the peripheral wall whose outer diameter is regulated to form a bottomed boss having a wall having a uniform thickness. It is characterized in that a bottomed boss is integrally formed on a part of the plate material through a boss forming step.

Therefore, according to the present invention, a desired bottomed boss can be efficiently formed on a part of a plate material in only two steps of a preliminary step and a boss forming step. Since it is formed very locally at an arbitrary position, there is no occurrence of distortion which affects the entire plate material.

Further, in the boss forming step in the method of the present invention, since the bottomed boss is formed not by elongation of the material but by crushing of the material as in the prior art, the height of the boss is relatively high (the plate thickness of the metal plate). Bottomed bosses, and the outer diameter can be formed with high accuracy.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, a schematic configuration of a press apparatus for performing a preliminary step in the method of the present invention will be described with reference to FIG.

FIG. 1 is a cross-sectional view of a main part of a press device. The press device includes an upper die 10 and a lower die 20.

The upper die 10 includes an upper die holder 11, an upper die punching backing plate 12, a die plate 13, and an upper die backing plate which are sequentially attached from the upper part to the lower part of the upper table 1 of the press machine. 14
And a die holder 15.
, A cylindrical button die 16 is fitted and held. Then, the die plate 13 and the upper backing plate 14
A cylindrical upper die punch 17 is vertically inserted into and held by the circular holes 13a and 14a respectively penetrating the lower die. I have.

On the other hand, in the lower die 20, reference numeral 21 denotes a lower die holder which is horizontally set on the lower table 2 of the press machine via a lower die spacer 22.
A punch holder 23 is fixed on the upper side.

A bolt 24 screwed vertically to the lower surface of the lower mold holder 21 has a cushion plate 25
Are inserted through the cushion plate 2 so as to be movable up and down.
A spring 27 is interposed between 5 and washer 26.

A plurality of spring pins 28 are erected on the cushion plate 25, and these spring pins 28 are attached to the lower mold holder 21 and the punch holder 2.
3 and project above the punch holder 23, and a blank holder 29 is horizontally mounted on the upper end thereof.

Further, a cylindrical lower die punch 30 is vertically inserted and held in a circular hole 23 a penetrating the punch holder 23, and the upper end of the lower die punch 30 is punched into the blank holder 29. It is inserted and held in the provided circular hole 29a. At the time of non-forming, the blank holder 29 is kept in a no-load state and is at the upper limit position by the spring 27. At this time, the upper surface of the lower die punch 30 is flush with the upper surface of the blank holder 29 as shown in the drawing. Holds state.

Next, a preliminary step performed using the press apparatus having the above-described configuration will be described with reference to FIGS.

FIGS. 2 and 3 are cross-sectional views of a main part of the press machine showing the preliminary steps in the order of the steps, and FIG. 4 is an enlarged detail view of a part A in FIG.

In the preliminary step of the method of the present invention,
As shown in FIG. 2, a metal plate 3 which is a plate material having a plate thickness T (= 1.8 mm) is placed on a blank holder 29 of the lower die 20.
Is placed and set, and the upper table 1 of the press is driven to move the upper die 10 downward, and a part of the metal plate 3 is preformed in a half-blanked shape as shown in FIG. 3 (preliminary step). .

In the preliminary step shown in FIG.
When the blank holder 29 is pressed downward by the upper die 10 to apply a load thereto, the blank holder 2
9, the spring pin 28 and the cushion plate 25 compress the spring 27 (see FIG. 1) and move downward by a predetermined amount. As a result, the lower punch 30 is moved from the upper surface of the blank holder 29 by a predetermined amount as shown in FIG. A part of the metal plate 3 protruding by 1 mm (1 mm) is preliminarily formed into a half-punched shape to form a projection 3a having a height h (= 2.6 mm) (see FIG. 4). This preliminary step regulates the flow direction of the material when the upper wall of the convex portion 3a of the metal plate 3 is crushed in the next boss forming step (see FIGS. 5 to 9), and the material moves upward. It is carried out for the purpose of preventing burrs from running away.

Incidentally, as shown in detail in FIG. 4, the outer diameter φD (= φ13
mm) is set to be larger (φD> φd) than the outer diameter φd (= φ8 mm) of the upper die 17, and the radius of curvature R ₂ of the arcuate curved portion (chamfered portion) formed on the inner peripheral edge at the lower end of the button die 16 is larger than the radius of curvature R ₁ of the arcuate curved surface portion formed on the upper end outer peripheral edge of the lower punch 30 (chamfered portion) (R ₂
> R ₁ ) has been set.

In the preliminary step, the metal plate 3
The thickness t of the upper wall of the half-bump-shaped convex portion 3a formed on a part of the metal plate 3 is substantially the same as the plate thickness T (1.8 mm) of the metal plate 3 (t ≒ T). Sagging occurs at the periphery.

As described above, when a half-bump-shaped convex portion 3a is formed in a part of the metal plate 3 by the preliminary process, the boss forming process shown in FIGS. You.

Here, a schematic configuration of a press device for performing the boss forming step will be described with reference to FIG.

FIG. 5 is a cross-sectional view of a main part of the press device. The press device includes an upper die 40 and a lower die 60.

In the upper die 40, reference numeral 41 denotes an upper die holder, reference numeral 42 denotes an upper die holder base mounted on the upper die holder 41, and an upper die holder 43 in the upper die holder 41 is vertically slid. The upper die holder 43 is movably fitted and held.
Are urged downward by a spring 44 compressed between them.

A cylindrical button die 45 is fitted and held in the upper die holder 43, and the upper surface of the button die 45 has a button die backing fitted on the upper part of the upper die holder 43. It is received by the plate 46. An upper punch holder 47 is disposed above the upper die holder 43, and an upper punch 48 is vertically inserted and held in the center of the upper punch holder 47. The upper die punch 48 has an upper surface received by an upper die backing plate 49, and a lower half thereof penetrates the button die backing plate 46 to face the inside of the button die 45, and has a lower end peripheral portion. Is fitted to the lower inner periphery of the button die 45 so as to be vertically movable.

The upper punch holder 47, the upper punch 48 and the upper punch backing plate 49 are urged downward by a spring 50 compressed between the upper punch base 47 and the upper die holder base 42. .

On the other hand, in the lower die 60, reference numeral 61 denotes a lower die punch holder, on which a lower die punch 62 is vertically held. A plurality of rods 63 extending upward from an air cylinder (not shown) are inserted through the lower punch holder 61, and a blank holder 64 is horizontally mounted on the upper ends of these rods 63.

The upper half of the lower die punch 62 is inserted into the blank holder 64 from below.
The outer periphery of the upper end of the lower punch 62 is provided with a blank holder 64.
Is movably inserted into a circular hole 64a formed in the hole. Also, the lower die punch holder 61 and the blank holder 6
A spring 65 is compressed between the four.

Next, a boss forming step performed by using the press apparatus having the above configuration will be described with reference to FIGS. 4 to 8 are cross-sectional views of a main part of the press device showing the boss forming steps in the order of the steps, and FIG. 9 is an enlarged detailed view of a part B in FIG.

At the time of the boss forming step, the metal plate 3 on which the half-bump-shaped convex portion 3a was formed in the preliminary step
5 is placed and set on the blank holder 64 of the lower die 60 as shown in FIG. 5, and when the upper die 40 is lowered from this state, the upper die punch 48 and the upper die holder 43 contact the upper surface of the metal plate 3. Touch

Then, when the upper die 40 further descends from the above state and the upper die holder base 42 comes into contact with the upper die punching backing plate 49 as shown in FIG. 6, the boss forming step is started. At this time, both springs 44,
50 is compressed by the descending stroke of the upper die holder 41 and the upper die holder base 42.

Thereafter, when the upper mold 40 is further lowered, FIG.
The upper wall of the convex portion 3a of the metal plate 3 is crushed by the upper punch 48 and the lower punch 62 as shown in FIG. Then, at the same time that the crushing is started, the rod 63 of the air cylinder that has pushed up the blank holder 64 is lowered.

Then, the material of the upper wall (the hatched portion in FIG. 9) of the thickness t before crushing of the convex portion 3a of the metal plate 3 starts to flow, and this material starts to flow as shown by the arrow in FIG. It flows along the peripheral wall whose outer diameter is restricted and flows downward. Then, the button die 45 urged by the spring 44 and the blank holder 64 urged by the spring 65 maintain a substantially balanced state (no-load state) when the urging force of the rod 63 of the air cylinder is lost.

Thus, the material which has flowed around due to the crushing of the projection 3a of the metal plate 3 as described above pushes down the button die 45, and lowers the peripheral wall having a uniform thickness t "from the upper wall of the projection 3a. Then, at the stage where the upper wall of the convex portion 3a is crushed until the upper wall becomes the thickness t ', the bottomed boss 3b having the height H and having the peripheral wall having the uniform thickness t "is formed on the metal plate 3. Molded integrally.

After the bottomed boss 3b is formed on the metal plate 3 as described above, when the upper die 40 starts to rise, the rod 63 of the air cylinder simultaneously rises.
Then, as shown in FIG. 8, when the upper die 40 rises, the upper die holder 41 and the button die 45 rise, and the bottomed boss 3 b formed on the metal plate 3 comes off the upper die 40.

Thereafter, when the upper die 40 further moves up and the upper die punch 48 separates from the upper wall of the bottomed boss 3b of the metal plate 3, the blank holder 64 pushed up by the rod 63 of the air cylinder is moved to the metal plate. 3
Since the bottomed boss 3b is removed from the lower punch 62, the metal plate 3 integrally formed with the bottomed boss 3b can be taken out. At this time, the air cylinder (not shown) is operated with a predetermined timing delay.

The outer diameter of the upper punch 48 used in the boss forming step (= the outer diameter of the bottomed boss 3b) φd ₀ is the outer diameter of the upper punch 17 used in the preliminary step shown in FIG. The outer diameter φD ₀ of the lower punch 62 is set to φD ₀ = φd ₀ −2t ″, which is set equal to or slightly larger than φd.

The thickness t "of the peripheral wall of the bottomed boss 3b formed integrally with a part of the metal plate 3 by the method of the present invention is at least 0.5 mm, and the height H is the thickness of the metal plate 3. Up to about three times T (H ≒ 3T).

Thus, according to the method of the present invention described above, the desired bottomed boss 3b can be efficiently formed on a part of the metal plate 3 in only two steps of the preliminary step and the boss forming step. Moreover, this bottomed boss 3b is a metal plate 3
Is formed very locally at any position of the metal plate 3, so that there is no occurrence of distortion which affects the entire metal plate 3.

In the boss forming step in the method of the present invention, since the bottomed boss 3b is formed not by elongation of the material but by crushing of the material as in the prior art, the height H (the metal plate 3) is relatively high. Up to about three times the thickness T (H の 3T) of the bottomed boss 3b can be formed with high precision.

[0044]

As is apparent from the above description, according to the present invention, a preliminary step of forming a convex portion by preforming a part of a plate material in a half-punched shape, and forming the convex portion by the preliminary step. By crushing the upper wall of the convex portion with upper and lower punches, the material of the upper wall is caused to flow to the peripheral wall whose outer diameter is regulated to form a bottomed boss having a wall having a uniform thickness. Since the bottomed boss is integrally formed on a part of the plate material through the boss forming process, an effect that a bottomed boss having a highly accurate outer diameter can be integrally formed on the plate material with a few steps can be obtained. .

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a press device for performing a preliminary step in a method of the present invention.

FIG. 2 is a sectional view of a main part of a press device showing a preliminary step in the method of the present invention.

FIG. 3 is a sectional view of a main part of a press device showing a preliminary step in the method of the present invention.

FIG. 4 is an enlarged detail view of a portion A in FIG. 3;

FIG. 5 is a cross-sectional view of a main part of a press device showing a boss forming step in the method of the present invention.

FIG. 6 is a cross-sectional view of a main part of a press device showing a boss forming step in the method of the present invention.

FIG. 7 is a cross-sectional view of a main part of a press device showing a boss forming step in the method of the present invention.

FIG. 8 is a cross-sectional view of a main part of a press device showing a boss forming step in the method of the present invention.

FIG. 9 is an enlarged detail view of a portion B in FIG. 7;

FIG. 10 is a cross-sectional view showing a connection structure of the members by caulking.

FIG. 11 is a sectional view showing a spring positioning structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper table of press machine 2 Lower table of press machine 3 Metal plate (plate material) 3a Convex part 3b Boss with bottom 10,40 Upper die 17,48 Upper die punch 20,60 Lower die 30,62 Lower die punch

Claims (1)

[Claims] 1. A preliminary step of forming a convex portion by preforming a part of a plate material in a half-punched shape, and crushing an upper wall of the convex portion formed on the plate material by the upper and lower punches in the preliminary step. Through the boss forming step of flowing the material of the upper wall to the surrounding wall whose outer diameter is regulated to form a bottomed boss having a wall of uniform thickness, the bottomed boss is integrated with a part of the plate material A press forming method for a bottomed boss, characterized by forming.