JPS641217B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to countersunk hole drilling, and particularly to a method that eliminates burrs on the back surface.

For example, in the manufacture of members such as aluminum sashes, countersinking for screw holes and the like is often performed. According to the plate drawing process that is currently being carried out, the first
As shown in the figure, since the member W set in the lower mold 1 is punched with the punch 2, it is inevitable that a burr W' is formed on the back surface of the member W due to countersunk drawing.
Therefore, when another member is assembled in close contact with the back surface of the member W, it is necessary to form a recess in the member to receive the burred portion W'. In addition, if this recess cannot be formed, countersunk processing must be performed to avoid burrs W'.

In view of the current situation, it is an object of the present invention to provide a countersunk hole drilling method for forming a hole without a burr on the back surface.

For this purpose, the present invention forms a countersunk drawing protrusion on the punch corresponding to the wall thickness of the workpiece, and works with the lower die to draw a countersink into the workpiece to a depth corresponding to the wall thickness. The method is characterized in that drawing is performed, and then the lower die is driven in the lateral direction along the back surface of the workpiece to cut out the bottom of the countersink drawing hole, thereby forming a desired countersink drawing hole.

Embodiments of the present invention will be described below with reference to FIGS. 2 to 5.

2 and 3 illustrate the basics of the method of the invention. That is, as shown in the figure, the punch 10 used does not have the protrusion 2A for punching holes as shown in FIG. 1, and has a height h (h=d) corresponding to the wall thickness d of the workpiece W. The punch has a countersunk projection 10A. On the other hand, the lower mold 20
1 does not have a dish-shaped recess for the dish diaphragm as seen in FIG. 1, but simply has a hole 20A formed therein. The diameter of the top of this hole 20A is the diameter of the punch 10.
It is appropriately set so as to cooperate with the countersunk drawing protrusion 10A to obtain a desired countersunk shape. Here, hole 20
A is a tapered hole that widens downward.

With such a punch 10 and lower die 20,
First, plate drawing is performed as shown in FIG. At this time, since the height h of the countersunk protrusion 10A of the punch 10 is equal to the thickness d of the workpiece W, its tip surface 1
0A' is located at the same level as the top surface 20' of the lower mold 20. Thereafter, as shown in FIG. 3, the lower die 20 is moved laterally along the back surface of the workpiece W as indicated by the arrow. At this time, the workpiece W is held while maintaining its relative position to the punch 10. As a result, the peripheral edge 20 of the top of the hole 20A of the lower mold 20
B functions as a cutter, shearing and cutting off the bottom portion W'' of the disk drawer. In this way, a countersink hole complementary to the disk drawer protrusion 10A is formed as shown in FIG. No protrusions such as burrs are formed on the back surface of the workpiece W.

FIGS. 4 and 5 illustrate one specific apparatus for carrying out the method of the present invention. This device includes a vertically movable slide 30 equipped with the punch 10 as described above, and a guide 31 (fourth
It has a bolster 32 that is movable in the lateral direction perpendicular to the plane of the paper of FIG. The punch 10 is attached to the slide 30 so as to be movable up and down against a compression spring 33 (FIG. 5), and the punch 10 cooperates with the hole 20A of the lower mold 20 to flatten the workpiece W. After processing, the slide 30 can be further lowered. The workpiece W is supported by the lower mold 20 and the holder 34, and is held relative to the holder 34, while the lower mold 20 is guided so that it can move along the back surface of the workpiece W. It is attached to 31.

In order to move the lower mold 20 in this manner, in this device, a cam 35 is fixed to a slide 30, and a driven member 36 (FIG. 5), which forms a cam hole 37 in the middle for receiving this cam 35, is moved downward. It is fixed to the mold 20. Here, in order to drive the lower die 20 in the left-right direction in FIG. 5, cam surfaces 35A and 35B are formed on both sides of the cam 35, and
cam hole 37 cam surfaces 30A, 37B on both sides of the cam hole 37
They are designed to engage with each other. The engagement by these cam surfaces 35A, 35B, 37A, and 37B keeps the lower mold 20 in a predetermined position (the position shown in the figure) until the slide 30 descends and countersunk drawing is performed by the cooperation of the punch 10 and the lower mold 20. However, after the countersink drawing is completed, the punch 10 is pushed up by the lower die 20 and the workpiece W which has been countersinked is sandwiched in the middle. The engagement moves the lower mold 20 to the left from the position shown in FIG. Move it in the opposite direction beyond the position shown.
It is designed to drive reciprocatingly. Here, the stroke of this reciprocating drive is the hole 2 that becomes the cutter.
The moving rear side of the top peripheral edge of 0A is moved from the outer diameter position of the bottom W'' (see Figure 2) to the center position or a position slightly beyond it, thereby shearing half of the bottom W'' of the disk drawing. It is selected to be removed as a whole.

According to this device, the workpiece W is first countersunk drawn by the cooperation of the punch 10 and the lower die 20 as described above, and then the workpiece W is drawn by the lower die 20 by the cooperation of the cam 35 and the driven member 36. is driven in the lateral direction to cut out the countersink drawing bottom W'', thereby achieving a countersink drawing hole with no burrs on the back surface.Moreover, this processing is all done in one stroke of the slide 30. be.

In addition to the embodiments described above, instead of the driving method of the lower die using the cam 35 and the driven member 36, a suitable cylinder device may be provided and the die may be driven independently in response to completion of countersunk drawing. It is also possible to cut out the countersunk bottom W'' by moving the lower mold only in one direction, and in this case, the lower mold can be configured to return using a tension spring.These configurations Although not shown in the drawings, it will be understood that this can be easily done, and that other structures are also possible.

As described above, the present invention can extremely easily achieve countersink hole drilling without any protrusions such as burrs on the back surface, and therefore can have great industrial effects in terms of simplifying the manufacturing process. That is clear.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a conventional countersunk hole drilling method. FIG. 2 is a sectional view showing the countersinking stage in the countersinking hole drilling method according to the present invention. FIG. 3 is a cross-sectional view showing a step of cutting the bottom of the countersink drawer subsequent to FIG. 2 in the countersink draw hole drilling method according to the present invention. Fourth
FIG. 5 is a front elevational view and a side elevational view, respectively, showing an embodiment of an apparatus for carrying out the countersunk hole drilling method of the present invention. d...Thickness of the workpiece, h...Height of the countersink drawing protrusion, W...Workpiece material, W''...Bottom of the countersink drawing, 10
...Punch, 10A...Counter drawing protrusion, 20...Lower mold, 20A...Hole, 20B...Periphery, 30...
Slide, 31... Guide, 32... Bolster,
33... Compression spring, 34... Holder, 35...
Cam, 35A, 35B... cam surface, 36... driven member, 37... cam hole, 37A, 37B... cam surface.

Claims (1)

[Claims] 1. A punch that is attached to a slide so as to be movable up and down and has a countersunk protrusion whose height corresponds to the wall thickness of the workpiece, and a punch that cooperates with the countersink protrusion to process the workpiece. Using a laterally movable lower mold which has a hole for countersinking the material, the punch and lower mold first perform countersinking in the first half of one slide stroke, and then While the punch and workpiece are held on the upper surface of the lower mold in a countersunk fit state, the lower mold is moved laterally along the back surface of the workpiece by the slide and interlocking means provided on the lower mold. This makes it possible to form a countersink hole having no protrusion on the back surface in one processing stroke by shearing and cutting the countersink bottom of the workpiece at the top periphery of the hole. A countersunk hole drilling method. 2. The countersunk hole drilling method according to claim 1, wherein the interlocking means comprises a cam fixed to the slide and a cam of a driven member provided on the lower die. 3. The countersink hole drilling method according to claim 1, wherein the interlocking means includes a cylinder device that drives the lower die in response to completion of the countersink drawing process. 4. Actuation of the cam drives the lower mold from the central position of the hole to a position larger than its radial direction, first in one direction and then in the opposite direction along the diameter, thereby causing the countersunk aperture. 3. The countersunk hole drilling method according to claim 2, wherein the bottom portion is sheared in half toward the center.