JPH01245926A - Pressing method - Google Patents

Abstract

PURPOSE:To improved production efficiency and to reduce production cost by protruding a cutting edge at the tip part of a die and executing partial finish of a work simultaneously in a punching stage. CONSTITUTION:A protrusion part 13 of the die is formed at part of a flat section 12 on the tip part 11 of the die 5. In this case, a clearance (d) between the protrusion part 13 and a punch 7 is set narrower than a clearance (f) between the flat section 12 and the punch 7. When punching is started by the lowering of a press 3, first, a shear surface is formed by the roundness B of the cutting edge 13a of the protrusion part 13 on the end face of a working part (a). Then, a little later on, the flat section 12 of the die bites into other sections of a steel sheet 2 and is punched. Because the necessary partial working in press working is carried out in the same press punching stage, the production efficiency of press working is improved and the production cost is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a press working method for partially finishing a pressed product within a press process.

Conventional technology In the conventional press working method, the punched cross section of a workpiece (steel plate, etc.) is a sheared area in a certain range from the top surface of the workpiece that comes into contact with the die, which is the punching member of the press machine, and the rest The part had become a fractured surface due to twitching of the member. Here, if at least a portion of the punched cross section of the press-formed product is required to have a long "bent surface" (shear surface) extending over the entire length or almost the entire length of the workpiece in the thickness direction, After the press working of a member is completed, a secondary process such as shaving of the fractured surface is performed separately from the press working at a location where one part needs to be finished.

For example, in FIGS. 6(1) and (II), the web 20 of a brake shoe used in a drum brake device, etc. has a thickness ratio of 6 in the web thickness direction only in the section a in FIG.
A long finishing surface (shearing surface) of 0% to 70% or more is required. Therefore, when processing the web 20, first a belt-shaped steel plate, which is a workpiece (not shown), is punched into a predetermined shape by press working (No. 6!1t(1)), and then a cross-section of the punched steel plate is The shaving process (FIG. 6 (II)) was performed only on the portion a that required a finished surface.

In addition, as another press processing method that does not require the above-mentioned two-way processing, a processing method called precision punching (fine blanking) is known, and this method produces a finished surface across the punched cross section of the workpiece. If necessary, the entire surface of the punched cross section will be finished at the same time during the pressing process.

The problem that the invention seeks to solve However, firstly, after the end of the pressing process.

Furthermore, partial finishing (secondary processing) for the pressed product
Implementing a separate process to perform this significantly reduces production efficiency and significantly increases production costs.

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

The present invention has been made to solve these problems, and provides a press working method that can achieve high production efficiency and low production costs at the same time by performing partial finishing of pressed products during the press process. The purpose is to

Means for Solving the Problems In order to achieve the above object, the press working method of the present invention includes forming a protrusion on at least a part of the tip of a die for punching in a press machine, and pressing the die with the protrusion on the die tip. Partial finishing of processed products is done during the press process.
It is characterized in that it is carried out simultaneously with the punching process in the press process.

Effect of the Invention The present invention has the above-described configuration, and when punching a die of a press device or a workpiece, the contact timing of the protruding part of the die tip with the workpiece is made to be earlier than the other non-protruding parts of the die tip, so that the liquid is released. A finished surface (a sheared surface that is longer than that formed on other punched sections) is formed only on the punched cross section that the die tip protrusion of the recessing member comes into contact with, so that partial finishing of the pressed product can be done during the pressing process. It is something to be done carefully.

Example Hereinafter, one embodiment of the present invention will be described based on the drawings.

As shown in FIG. 1, a press working apparatus 1 used in the press working method of the present invention is for press working a web 20 for a brake shoe of a drum brake device, and is mainly used to press a web 20 for a brake shoe of a drum brake device. a punch 7 for placing the
A knockout 6 is attached to a press stand 3 to be described later with an elastic member 9 such as a damper, and presses the band-shaped steel plate on the punch with a preset pressing force of the elastic member during press processing to position it. A die 5 for punching out the knockout outer contour of the belt-shaped steel plate 2 that is positioned and fixed by the knockout, and a stripper 8 that engages with the die, and the die 5 and the knockout 6 are attached and can move up and down in the vertical direction. Press stand 3 and punch 7
and a press stand 4 that supports and fixes the slippers 1 to 8.
location map).

The tip portion 11 of the die 5 includes a die flat portion 12 and a die protruding portion 1 that at least partially protrudes from the flat surface of the die flat portion.
3, and the inter-tool gap distance d (0,05no) (hereinafter referred to as clearance) between the die protrusion 13 and the punch 7 is narrower than the clearance f (0,45+m) between the die flat part 12 and the punch 7. It is set.

FIG. 3 is a plan view of the press processing apparatus 6 (with the press table 3 removed). A in the figure is the shape of the processed product, that is, the cross-sectional shape of the knockout 6. This indicates a part of the shape that requires special finishing. When punching out the strip steel plate 2 with the die 5.

The die protruding part 13 comes into contact with the a part of the machining shape A and performs punching and partial finishing of the workpiece, and the die flat part 12 punches other parts of the machining shape A except for the a part. conduct.

One effect will be explained below.

A strip steel plate 2 (thickness: 3.811Wll) is fed between the die 5, knockout 6, punch 7, and stripper 8 of the press processing apparatus 1 by a feed device (not shown), and
It moves one pitch for each reciprocating movement. Here, when the press punching operation is started by lowering the press stand 3, the strip steel plate 2 is positioned and fixed on the punch 7 by the knockout 6.

In this positioning and identified state, the die 5 further descends along the outer contour of the knockout 6, and first the die tip 11
The die protrusion 13 is inserted into the a section of the strip steel plate 2. Then, the roundness B formed on the cutting edge 13a of the die protrusion 13
(R=0.3), the stress concentration on part a of the strip steel plate 2 during press punching is relaxed, and the punched end surface of the part a starts to form a sheared surface on the side of the protruding part. Next, after a slight delay, the die flat part 12 of the die tip 11 sinks into the other part of the strip steel plate 2. At this time, the die protruding part 13 has already preceded the die flat part 12 by 0 minutes (2,511n). Although it is embedded in the steel strip, a sheared surface is still formed at the punched part.

Conventionally, the punched cross-sectional shape of the member that contacts the die protrusion 13 located at a position lowered by about 60% of the total length of the plate would be a fractured surface, but the die protrusion compared to the die flat part 12 During punching, the part 13 contacts and shears only the parts that require partial finishing at an early timing, and the clearance d between the die protruding part 13 and the punch 7 is set narrower than the clearance f between the die flat part 12 and the punch 7. The occurrence of the fracture surface 20b due to the twitching of the member is suppressed.

As a result, a of the workpiece 20 punched by the die 5
Shear plane 20a longer than normal (usually 0.8m) only in the part
A finished surface of (2.8 mm) is obtained, and within the pressing process, partial finishing of the pressed product is achieved at the same time as punching.

Note that the present invention is not limited to the above-mentioned embodiments.1 For example, as in the press processing apparatus shown in FIG. 4, a die protrusion 13 provided with a cutting edge is provided separately from the die, and It may be detachable via a mounting member such as a screw 14, and the mounting position may be determined depending on the desired partial finishing position of the processed product or the processed shape (installation of multiple protruding blades is also possible).
Or the installation can change conditions. Akira am again
Also, the numerical values shown in the drawings are not limited thereto.

Effects As explained above, according to the present invention, by performing partial finishing of the pressed product during the pressing process,
It is possible to realize a press working method that can simultaneously achieve high production efficiency and low production costs.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of the press working apparatus at the position shown in line 1-1 in Fig. 3 immediately before punching out a strip steel plate by the press working apparatus of the present invention, and Fig. 2 shows the state after punching the band steel plate. FIG. 3 is a side sectional view of the press working device similar to FIG. 1, FIG.
The figure shows a side cross-sectional view of another press processing device similar to that of FIG.
Figure 1 is a partial perspective view of a workpiece punched using the processing method of the present invention, Figure 6 is a workpiece processed using a conventional processing method, and (I) is a partial perspective view of a workpiece punched using a conventional press processing device. (II) is a partial perspective view of the processed product. It is a partial perspective view of the processed product in which the edge portion of the processed product has been subjected to a shaving process. In the figure, 1... Press processing device, 2... Strip steel plate, 3
... Press stand, 5 ... Die, 6 ... Knockout, 7 ... Punch, 8 ... Stripper, 11 ... Tip of die, 12 ... Flat part of die, 13. ...Die protrusion, 13a... Cutting edge of the die protrusion, 20... Web, 20a... Sheared surface of the web, 20b... Fractured surface of the web. Utility model registration applicant: Akebono Brake Industry Co., Ltd. Agent
Patent Attorney: Hiroshi Kisumi Figure 2 (I) (II) Figure 6 Procedure Amendment Band (Voluntary) May 25, 1985 Director General of the Patent Office Kunio Ogawa L., Indication of the Case 1988 Patent Application No. 70861 2, Name of the invention Press processing method 3, Person making the amendment Address: 103 Relationship to the case Patent applicant address: 19-5 Nihonbashi Kokinumachi, Chuo-ku, Tokyo
(051) Akebono Brake Industry Co., Ltd. Representative Makoto
Moto Yasu Tei 4, Agent 101 Telephone 865-4925 Address 501 Kakuhari Building, 1-7-9 Higashikanda, Chiyoda-ku, Tokyo Figure 1 of the drawings 6, Contents of amendments

Claims (2)

[Claims] (1) A press working method characterized by performing partial finishing on a press work product during the press process. (2) A press working method characterized in that partial finishing of a press work product is performed during a punching press process of the work product using a cutting edge protruding from a part of the tip of a die.