JP2002011526A - Burring die apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem such that in burring a fin, etc., while the clearance between a burring punch and a die is narrowed, ironing is conducted, a height of burring has make high, but a significant deviation in the burring height is caused by a minute deviation of the clearance, further there is some limit to align upper/lower dies. SOLUTION: The burring punch 1 is fixed, a die 5 is held freely slidably in the radial direction, thus, the clearance between the burring punch 1 and the die 5 is made uniform, the variance in burring heights and breaking of burring due to the deviation of clearances are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burring die, and more particularly to a burring die capable of forming a heat exchange fin or the like with a uniform height without breaking when the flange is formed by flange processing. Regarding the mold.

[0002]

2. Description of the Related Art The heat exchange fins are formed by arranging a large number of burrings on a rectangular aluminum plate at equal pitches, flaring the ends thereof, stacking several burrings, and forming a burring hole through a copper tube. It is important to carry out burring with a uniform height without cracking or breakage at times. However, when performing burring on a thin aluminum plate, it is difficult to perform burring with a uniform height without cracking or breakage because the clearance between the burring punch and the die is biased. FIG. 5 shows a conventional mold in which a die is fixed and a burring punch is movable.

In the drawing, reference numeral 1 denotes a burring punch movable up and down by a punch plate, 2 denotes a pad, 3 denotes a punch plate, 4 denotes a backing plate, 5 denotes a die fixed to the die plate, 6 denotes a die plate, and 7 denotes a die plate. Is a gap formed between the die 5 and the die plate, 8 is a die backing, and 9 is a workpiece. The bottom surface of the burring punch 1 has a spherical shape, and when the burring punch 1 is inserted into the fixed die 5, the burring punch 1 can be tilted by the amount of the center deviation between the burring punch 1 and the die 5. It has a structure.

[0004]

However, in a conventional die in which the die 5 is fixed and the burring punch 1 is movable, the burring punch 1 has a structure longer than the die 5 and tends to be inclined. ,
It is difficult to secure a uniform clearance all around the burring punch 1 and the die 5. Therefore, FIG.
As shown in FIG. 6, the burring height becomes non-uniform, and breakage occurs as shown in FIGS. 6A and 6B, resulting in defective products as heat exchange fins.

[0005]

According to the present invention, a burring punch is fixed, and a gap of 1/2 or less the thickness of a workpiece is provided between a die and a die plate. The structure is such that it can slide in the radial direction. By contacting the wide bottom surface of the die and the die plate with the pad into which the burring punch is inserted, the die can slide in the radial direction without tilting and maintain uniform clearance. The molding process can be performed while securing a uniform clearance.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a burring punch fixed to a punch plate and having a vertically movable pad inserted therein, and a burring punch held by a vertically movable die plate. In a burring die apparatus provided with a die that fits into the die, the burring punch is fixed, and a gap of 1/2 or less the thickness of the workpiece is provided between the vertically movable die and the die plate. It is characterized by securing a uniform clearance between the burring punch and the die through the workpiece during burring by allowing sliding in the radial direction, and through the workpiece during burring. It has the function of keeping the clearance between the burring punch and the die uniform.

According to a second aspect of the present invention, a bearing is interposed between the back surface of the die and the die backing to reduce the sliding resistance of the die. This has the effect of keeping the clearance between the burring punch and the die uniform, and the effect of allowing the die to slide smoothly.

Further, in the present embodiment, the gap between the die and the die plate is set to be equal to or less than 1/2 of the thickness of the workpiece, but if the gap exceeds 1/2, the center deviation between the burring punch and the die is corrected. The gap is set to １ ／ or less of the plate thickness of the workpiece in view of exceeding the possible range and the limit of preventing the die from falling down. (Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1, 2 and 3. FIG.

FIG. 1 shows a method of holding a burring punch and a die of a burring die according to the present invention.
Is fixed to the punch plate 3, and a pad which can move up and down is fitted. The die 5 is held on a die plate 6,
The distance between the die 5 and the die plate 6 is 1 / th of the thickness of the workpiece 9.
Two or less gaps 7 are provided so that the die 5 can slide in the radial direction.

FIG. 2 shows another method of holding a burring punch and a die of a burring die according to the present invention. The burring punch 1 is fixed to a punch plate 3, the die 5 is held by a die plate 6, and the dies 5 and A gap 7 is provided between the plates 6 that is less than half the thickness of the workpiece 9 so that the die 5 can slide in the radial direction. , A bearing 10 is provided between the back surface of the die 5 and the die backing 8.

FIG. 3 shows a burring step, in which (a) shows a state before processing, (b) shows a state during processing, and (c) shows a processing end.
As shown in FIGS. 3A and 3B, when the upper die is lowered, the workpiece 9 is clamped between the pad 2 and the die plate 6, and the burring punch 1 is inserted into the burring hole 9a of the workpiece 9. Along the way, the burring pilot hole 9a is expanded to the diameter of the burring punch 1 and insertion into the die 5 is started. At this time, if the center of the burring punch 1 is shifted from the center of the die 5, the die 5 moves on the same center as the burring punch 1 due to the gap 7 between the die 5 and the die plate 6, so that a uniform clearance can be maintained. The non-defective product shown in FIG. 4 can be formed.

In this embodiment, the lower die is provided with the burring punch, and the upper die is provided with the die. However, the same operation can be performed even if the upper die is turned upside down.

[0013]

As described above, according to the present invention, it is possible to obtain a uniform burring height by making the die slidable in the burring process, and it is possible to obtain an effect of improving product defects. Further, even when the heat exchange fins are not broken, burring having a uniform height can be obtained, and an effect of improving product defects can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a burring punch and a die according to the present invention.

FIG. 2 is a schematic view showing a burring punch, a die, and a bearing according to the present invention.

FIG. 3 is a schematic view showing a burring process in the present invention.

FIG. 4 is a view of a product formed in the present invention.

FIG. 5 is a schematic view showing a conventional mold structure.

FIG. 6 is a view showing a defective product formed by a conventional mold structure.

[Explanation of symbols]

 Reference Signs List 1 burring punch 2 pad 3 punch plate 4 backing plate 5 die 6 die plate 7 gap 8 die backing 9 work material 9a burring pilot hole 10 bearing

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiro Murakami 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 4E050 AA14

Claims (2)

[Claims] 1. A burring die apparatus comprising: a burring punch fixed to a punch plate and fitted with a vertically movable pad; and a die held by a vertically movable die plate and fitted to the burring punch. The burring punch is fixed, and a gap of 1/2 or less of the thickness of the workpiece is provided between the vertically movable die and the die plate so that the die can slide in the radial direction. A burring die apparatus which secures a uniform clearance between a burring punch and a die via a workpiece. 2. The burring die apparatus according to claim 1, wherein a bearing is interposed between the back surface of the die and the die backing to reduce the sliding resistance of the die.