JP2663274B2 - Press working method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press working method for partially finishing a pressed product in a pressing process.

Conventional technology Workpiece (steel plate etc.) in conventional press working method
Was a shearing section in a certain range from the upper surface of a workpiece to be contacted with a die which is a punching member of a press device, and most of the remaining sections were fractured due to tightness of the member. Here, when a long finished surface (shear surface) over the entire thickness or substantially the entire thickness in the thickness direction of the workpiece is required for at least a part of the punched cross section of the pressed product, the press for the workpiece is performed. After the processing, shaving processing or the like on the fractured surface is performed separately from the press processing as a secondary processing for a portion where partial finishing is required.

For example, in FIGS. 6 (I) and (II), a web of a brake shoe used for a drum brake device or the like is shown in FIG.
Indicates that only the portion a in the drawing has a thickness ratio of 60% or more in the web thickness direction.
A long finished surface (shear surface) of 70% or more is required. For this reason, when processing the web 20, first, a strip-shaped steel plate, which is a workpiece (not shown), is punched into a predetermined shape by press working (FIG. 6 (I)). Shaving processing (FIG. 6 (II)) was performed only on the portion a where a surface was required.

As another press working method which does not require the secondary working, precision punching (fine blanking) is used.
A known processing method is known in which, when a finished surface is required over the entire punched cross section of a workpiece, the entire punched cross section is simultaneously finished in a pressing step.

Problems to be Solved by the Invention However, firstly, after the completion of the pressing step, performing another step to further perform a partial finishing (secondary processing) on the pressed product means that the efficiency of production is reduced. This significantly reduced the production cost.

Second, in precision punching as another processing method, even if only partial finishing is sufficient, the entire punched cross section is formed as a finished surface, and the press processing equipment used for this processing is very expensive Therefore, the production cost is higher than that of the secondary processing, and there is a limit in reducing the cost.

The present invention has been made to solve such problems.
It is an object of the present invention to provide a press working method capable of simultaneously achieving high production efficiency and low production cost by performing partial finishing of a pressed product in a pressing process.

Means for Solving the Problems In order to achieve the above object, a press working method of the present invention comprises: forming a protruding portion that protrudes in a press stroke direction at a part of an inner edge of a die tip for die punching in a press working device. Then, when the die punches the workpiece, the contact timing of the projecting portion to the workpiece is set ahead of the non-projecting portion, so that the finished surface is formed only on the punched cross section where the projecting portion of the workpiece contacts. Formed, and a finishing process for a part of the cut surface of the pressed product is performed in the cutting process.

When the die of the punching press device punches a workpiece, the above-mentioned protruding portion at the tip of the die first reaches the workpiece and shearing is started, and subsequently, the other tip of the die contacts the workpiece. And the shearing begins. When the shearing by the other end of the die which does not form the protruding portion progresses to some extent, the workpiece is broken along the shape of the die and punched. Therefore, the shear surface of the cut surface due to the protrusion of the die is longer in the plate thickness direction than the shear surface of the cut surface due to the other end of the die, and the cut surface due to this protrusion is smooth to the extent that the finish processing is not particularly required. become.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a press working apparatus 1 used in the press working method of the present invention is used for pressing a web 20 for a drum brake device brake shoe, and mainly a strip-shaped steel plate 2 which is a member to be processed. Punch 7 for placing
And a knockout 6 which is attached to a press table 3 to be described later with an elastic member 9 such as a damper, and presses the strip-shaped steel plate on the punch with a preset pressing force of the elastic member to perform positioning during press working. A die 5 for punching the knockout outer contour of the strip-shaped steel plate 2 positioned and fixed at the knockout to form a processed product, a stripper 8 engaging with the die, and the die 5 and the knockout 6 are attached and vertically mounted. It is composed of a press table 3 that can be raised and lowered and a press table 4 that supports and fixes the punch 7 and the stripper 8 (FIG. 1 is an I of FIG. 3 described later).
-I side sectional view).

The tip 11 of the die 5 is formed from a die flat portion 12 and a die protrusion 13 at least partially protruding from the flat surface of the die flat portion, and a tool gap distance d () between the die protrusion 13 and the punch 7. 0.05 mm) (hereinafter referred to as clearance) is set smaller than the clearance f (0.45 mm) between the die flat portion 12 and the punch 7.

FIG. 3 is a plan view of the press working apparatus 1. (The press table 3 is removed) A in the figure shows the shape of the processed product, that is, the cross-sectional shape of the knockout 6. In the figure, "a" shows a portion requiring special finishing in the processing shape A. When the strip-shaped steel plate 2 is punched by the die 5, the die protruding portion 13 comes into contact with the a portion in the processing shape A to perform punching and partial finishing on the processed product, and the die flat portion 12 forms the a in the processing shape A. Punching is performed on other parts except the part.

 Hereinafter, the operation will be described.

The strip-shaped steel sheet 2 (having a thickness of 3.8 mm) is supplied between the die 5, the knockout 6, the punch 7, and the stripper 8 of the press working apparatus 1 by a feed device (not shown), and moves by one pitch for each reciprocation of the die 5. . Here, when the press punching operation is started by lowering the press table 3, the strip-shaped steel plate 2 is positioned and fixed on the punch 7 by the knockout 6. In this fixed state, the die 5 further descends along the outer contour of the knockout 6, and first, the die protrusion 13 of the die tip 11 enters the a portion of the strip-shaped steel plate 2.
Then, the roundness B formed on the cutting edge 13a of the die protrusion 13 is formed.
By (R = 0.3), stress concentration on the a portion of the strip-shaped steel plate 2 at the time of press punching is relieved, and the punched end surfaces of the a portion sequentially descend toward the protruding portion side and start forming a shear surface. Then, slightly later, the flat part of the die tip 11
12 is inserted into other portions of the strip-shaped steel plate 2. At this time, the die protruding portion 13 has a step C (2.5 mm) larger than the die flat portion 12.
Although the steel sheet is inserted into the strip-shaped steel sheet in advance, a sheared surface is still formed at the punched portion. In the conventional case, the punched cross-sectional shape of the member that contacts the die protrusion 13 located at a position about 60% lower than the full thickness of the plate thickness was a broken surface, but the die protrusion compared to the die flat portion 12 Early contact with only the parts that need to be partially finished by part 13,
Due to the shearing and the clearance d between the die projection 13 and the punch 7, which is set to be smaller than the clearance f between the die flat portion 12 and the punch 7, the generation of the fracture surface 20b due to the tightness of the member at the time of punching is suppressed.

As a result, a of the processed product 20 punched by the die 5
20a (2.8m) longer than normal (normally 0.8mm)
m) is obtained, and in the pressing process a partial finish on the pressed product is achieved simultaneously with the stamping.

Note that the present invention is not limited to the above-described embodiment. For example, as in the press working apparatus shown in FIG. It may be detachable via a mounting member such as a screw 14, and the mounting position (a plurality of protruding blades can be mounted) or the mounting state is changed according to the desired partial finishing position of the processed product or the processed shape. be able to. The numerical values described in the specification or the drawings are not limited thereto.

Effects As described above, according to the present invention, a press working method capable of simultaneously achieving high production efficiency and low production cost can be realized by performing partial finishing of a pressed product in a pressing step.

[Brief description of the drawings]

FIG. 1 is a sectional side view of the press working device at the position of line II in FIG. 3 immediately before punching the steel plate by the press working device of the present invention, and FIG. FIG. 3 is a side cross-sectional view of a press working device similar to FIG. 1, FIG. 3 is a cross-sectional view of the press working device taken along the line II-II in FIG.
FIG. 5 is a side sectional view of another press working device similar to FIG. 1 in which a die protruding portion provided with a cutting edge is provided separately from a die body, and FIG.
FIG. 6 is a partial perspective view of a processed product punched by the processing method of the present invention, and FIG. 6 is a processed product processed by a conventional processing method. FIG. 6 (I) is punched by a conventional press processing device. (II) is a partial perspective view of the processed product obtained by shaving the end of the processed product. In the figure, 1 ... press working device, 2 ... strip steel plate, 3 ...
Press stand, 5 ... Die, 6 ... Knockout, 7 ... Punch, 8 ... Stripper, 11 ... Die tip, 12 ...
Flat part of die, 13 ... Die protruding part, 13a ... Cutting edge of die protruding part, 20 ... Web, 20a ... Web shear plane, 20b ...
... A broken surface of the web.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masami Nishida 1190 Okamo, Iwatsuki-shi, Saitama Prefecture Akebono Brake Industry Co., Ltd. Brake Industry Co., Ltd. Iwatsuki Works (56) References JP-A-49-109988 (JP, A) JP-A-61-138423 (JP, U)

Claims (1)

(57) [Claims] A stamping die is formed on a part of an inner edge of a die for punching in a press working device. The protrusion projects in a direction of a stroke of the press. By setting the contact timing of the protruding portion ahead of the non-protruding portion, a finished surface is formed only on a punched cross section where the protruding portion of the workpiece contacts, and the finishing process on a part of the cut surface of the pressed product is cut. A press working method characterized by being performed in a process.