JPH11207412A - Method and device for burring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a concentricity precision of a prepared hole, a shape precision, a relative position precision and a concentricity precision of a burring hole by conducting burring from an outside of a flange part toward an inside in cooperation of both a slide die and a burring punch slidable thereto in the prepared hole axial line direction. SOLUTION: When butting first, second slide dies 5, 6 each other, an other drive cam in delaying thereto is slided with each slide cam and starts advancing motion so as to approach each slide cam. When a work W is clamped by a sectional pad, in accompanying advancing motion of each slide cam, burring punches 32, 33 are pressed into a die hole 27 with expanding a prepared hole formed to a flange part F. A burring flange part Fb is bent so as to expand the prepared formed to the flange part F of the work W, a burring hole B is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a burring hole by bending a burring flange portion while expanding a prepared hole, and more particularly, to a web and opposite sides of the web. The present invention relates to a burring method in which a workpiece formed in a substantially U-shaped cross section with a bent flange portion has improved shape accuracy and concentric accuracy of burring holes formed in each flange portion.

[0002]

2. Description of the Related Art As shown in FIGS. 10 and 11, for example, when a panel-shaped work W having a substantially U-shaped cross section having two burring holes B located on the same axis is formed, the developed shape of the work W, that is, A piercing process and a burring process of a prepared hole are performed in a flat plate shape, and finally, a forming process is employed in which a cross section is bent into a U-shape as a forming process.

[0003]

When the material W which has been subjected to the piercing and burring processing as described above is bent into a U-shaped cross section, press forming is performed using an inner die and an outer die. However, when processing is performed using an inner die having a shape faithful to the inner shape of the U-shaped work W, the burring flange portion Fb inevitably interferes with the inner die, and it becomes difficult to extract after processing. Therefore, a portion of the inner die that interferes with the burring flange portion Fb is locally released. However, if the relief portion is formed, the burring flange portion Fb is not sufficiently restrained at the time of bending, and the burring flange portion becomes insufficient. It becomes difficult to obtain the shape accuracy around the portion Fb, and the relative accuracy of the two burring holes B, B must be reduced.

[0004] Conversely, it is conceivable to perform piercing and burring of a pilot hole after performing a U-shaped bending first, but the precision is deteriorated due to the interference of the burring flange portion Fb. The problem cannot be solved yet.

The present invention has been made in view of the above-mentioned problems, and is based on the premise that piercing and burring of a pilot hole are performed after U-shaped bending, and that interference of burring flanges is prevented. An object of the present invention is to provide a burring method and a burring apparatus capable of effectively solving the problem and greatly improving the shape accuracy of each burring hole and the relative position accuracy and concentric accuracy of both burring holes.

[0006]

According to the first aspect of the present invention, there is provided a work having a substantially U-shaped cross section formed by a web and flange portions formed on both sides of the web so as to be bent to face each other. A method of forming burring holes located on the same axis with each other in a flange portion, wherein a step of bending a plate-shaped material into a substantially U-shaped cross section to form a work into a predetermined shape, and opposing each other among the works. Forming a pilot hole by piercing from the outside of each flange portion to the inside of each flange portion to form a pilot hole, and inserted into the U-shaped space of the work and in the longitudinal direction of the work and Two slide dies that can be approached and separated from each other in the longitudinal direction of the work with a dividing surface that is almost perpendicular to each of the axes of the pilot holes, By cooperating with a burring punch capable of riding, a burring process is performed from the outside to the inside of each flange portion where the prepared hole is formed, and the burring flange portion is bent and formed while expanding the prepared hole. And forming a burring hole by the method.

According to a second aspect of the present invention, a work preliminarily formed into a substantially U-shaped cross section by a web and flange portions bent and formed on both sides of the web so as to face each other is provided on each of the flange portions. An apparatus for forming a burring hole located on the same axis with each other, wherein a lower die is provided on a lower holder and forms a lower die together with the lower holder. By being placed with the open portion of the U-shaped space facing downward, the die that fits inside the work and positions the work is elastically supported by the upper holder so as to be able to move up and down. The upper die is formed together with the upper holder, and the pad for pressing and restraining the work on the die by the processing operation of the upper die is located on the lower holder and on the extension axis of the pilot hole. The burring flange is bent while the workpiece is slid by being driven by a cam in response to the lowering operation of the upper die and cooperating with the die to expand the prepared hole. And a pair of burring punches for forming a burring hole by molding.

The die is formed of a fixed locating die for positioning the work, and a pair of slide dies that are bisected in the longitudinal direction of the work with a vertical dividing surface passing through the axis of the prepared hole. Along with
The respective slide dies are configured so as to be able to approach and separate from each other, and each slide die is driven by a cam prior to the slide operation of the burring punch in accordance with the lowering operation of the lower die, so that the divided surfaces of both slide dies are separated. The burring punch and the burring punch are formed so that they are brought into contact with each other on the axis of the pilot hole.

According to a third aspect of the present invention, in the second aspect of the present invention, a concave portion corresponding to a half-shape of a die hole is formed in a divided surface of each slide die. It is characterized in that a die hole is formed by these recesses at the time of butting.

According to a fourth aspect of the present invention, one of the divided surfaces of each slide die in the third aspect of the invention has a V-groove shape, and the other has a mountain shape corresponding to the V-groove shape. It is characterized in that it is formed so as to exhibit an automatic centering function when the two divided surfaces abut against each other.

Therefore, according to the first aspect of the present invention,
Since the pilot hole is formed by piercing on each flange after performing the U-shaped bending of the work, the pilot hole is processed before the U-shaped bending if the accuracy on the piercing device side is secured. Compared with the case, the concentric accuracy between the prepared holes is surely improved.

Then, burring is performed following the piercing of the prepared hole. At this time, the burring is substantially perpendicular to both the axis of the prepared hole and the longitudinal direction of the work itself. By using two slide dies divided into two with such a divided surface, even if the burring flange portion interferes with the slide die during burring and cannot be removed, both dies are removed after burring. If the slide dies are separated from each other, the above-described interference relationship can be easily avoided, and the work can be extracted from those slide dies. Thereby, in a state where both slide dies abut against each other, the shape of the slide dies can be a shape faithful to the inner shape of the work, so that not only the shape accuracy of each burring hole, but also The relative positional accuracy and concentric accuracy between the burring holes can be greatly improved.

According to the second and third aspects of the present invention, the first aspect is provided.
Assuming the burring method in the invention described in the above, it is a more concrete form of a press-type structure which is a processing device that controls the burring, and at the time of burring, two slide dies are formed into a shape faithful to the inner shape of the work. As a matter of fact, the burring process is performed while cooperating with the corresponding burring punch while sufficiently constraining the periphery of the burring hole with pressure. After the burring process, wait for the burring punch to retract from the slide die and separate each slide die from each other,
Interference between the burring flange and the slide die can be avoided without difficulty.

According to the fourth aspect of the present invention, when the two slide dies abut against each other, the two surfaces are automatically aligned by the engagement of the V-grooves between the divided surfaces, and the accuracy of the burring flange portion is determined by the die hole itself. Shape accuracy is guaranteed.

[0015]

According to the first to third aspects of the present invention, the preparation of the prepared hole is performed following the U-shaped bending of the work, and finally, the burring punch and the die are cut at a position where the die hole is substantially bisected. Since the burring process is performed with a splittable slide die, the two pilot holes are processed and the burring holes are processed after determining the flange shapes facing each other, so the concentric accuracy of the pilot hole is of course In addition, the burring hole shape accuracy, relative position accuracy and concentric accuracy are greatly improved. In particular, at the time of burring, even if the burring flange portion and the slide die interfere with each other, the above interference can be easily resolved after the processing, so that at the time of burring, both slide dies are faithful to the inner shape of the work. It can be used as a shape, and as a result, it can be processed with the pressure around the burring flange, which is the burring hole, more than enough, so the shape accuracy and relative position accuracy of the burring hole are greatly improved. There is. At the same time, there is an advantage that the work can be processed by the transfer press because the work can be easily extracted after the processing.

According to the fourth aspect of the present invention, the self-aligning function is exhibited by the engagement of the V-groove at the time when the divided surfaces of both slide dies abut each other. In addition to this, there is an effect that the roundness accuracy or the shape accuracy of the die hole is improved, and the shape accuracy and the concentric accuracy of the burring hole are further improved.

[0017]

1 to 9 show a preferred embodiment of the present invention, and show a press die structure for forming a work W such as a link member of a suspension system of an automobile. The work W is formed so as to be wide while its central portion is curved upward, while both ends thereof are formed as a relatively narrow cross-section having a substantially U-shape. As shown in FIG. A burring hole B is formed by a press die on a flange portion F formed on both sides of a web E of one end portion Q so as to face each other. However, it is assumed that the pilot hole serving as the burring hole B has been formed in advance in the previous step.

FIG. 2 shows a state in which the upper die 10 has reached the bottom dead center, FIG. 3 shows a schematic plan view of the lower die 9, and FIG. ing.

First, an outline of the entire press mold will be described with reference to FIGS. 2 to 5. 1 is a lower holder fixed to a bolster (not shown), and 2 is a lower holder fixed to a press ram (slide) not shown. This is an upper holder that moves up and down with respect to the holder 1. On the lower holder 1, a die 3 composed of a fixed locating die 4 and a pair of left and right slide dies 5, 6 is arranged. On the die 3, a work W is positioned and mounted by a locating pin 7, This work W is pressed and constrained by the pad 8 on the upper die 10 side. As shown in FIGS. 3 and 4, a pair of burring punches for burring, which will be described later, are sandwiched between both ends of the work W positioned on the die 3 with a terminal portion Q to be burred. 32 and 33 are arranged facing each other. Then, the lower die 9 is formed by the lower holder 1, the die 3, the burring punches 32, 33, and the like.
On the other hand, the upper die 10 is formed by the upper holder 2, the pad 8, and drive cams 23, 24, 43, which will be described later, and the drive cams 23, 24 on the upper die 10 side in response to the lowering operation of the upper die 10. When the respective slide dies 5 and 6 are driven and the respective burring punches 32 and 33 are similarly driven by another drive cam 43 on the upper die 10 side, the burring of the burring hole B is performed. Become.

Next, the details of the lower mold 9 and the upper mold 10 will be described with reference to FIGS. 1 to 9. As shown in FIGS. The die 4 is fixed, and four locating pins 7 are erected on the upper surface thereof via a locating pin holder 11.
Then, by locating the locate holes H preformed on the work W side with these locate pins 7,
The work W is positioned with the open sides of the U-shaped spaces at both ends facing downward.

On the lower holder 1, a locating die 4 is provided.
2 and a relatively small second slide die 6 adjacent to the first slide die 5 are arranged so as to be located on the same axis with each other. A sectional die 12 is integrally fixed to the left end of the first slide die 5. These first and second slide dies 5 and 6 are provided with a guide pin 13 or 14 and an elongated hole-shaped guide groove 15 engaged therewith.
Or 16 and the stroke S ₁ or S ₂ regulated by
2 (see FIG. 2), the first slide die 5
2 is moved rightward in FIG. 2 by a return spring 17 provided between the second slide die 6 and the locating die 4.
Are urged to the left in FIG. 2 by return springs 18 provided between the first and second slide dies 5, respectively. Also, an inclined cam surface 19 or 20 is formed on each of the upper corners of the first and second slide dies 5 and 6, so that each slide die 5 and 6 functions as a slide cam. . That is, in FIG. 2, the first and second slide dies 5, 6 advance most toward the other party, respectively, and their end faces abut each other, more specifically, the sectional view of the first slide die 5. This shows a state where the left end surface 12a of the die 12 and the right end surface 6a of the second slide die 6 abut against each other. Therefore, the die 3 includes the fixed locating die 4 and the abutting surface (divided surface). Surface) 12a,
The first and second slide dies 5 and 6 are divided into right and left by 6a.

On the lower holder 1, backup blocks 21 or 22 are fixed on both sides of the die 3, while the upper holder 2 has an inclined cam surface corresponding to each slide die 5, 6. When the drive cam 23 or 24 having the drive cam 23a or 24a is fixed, FIG.
As shown in FIG. 5, the respective drive cams 23 and 24 slide on the first and second slide dies 5 and 6 while being guided by the backup blocks 21 and 22 in accordance with the lowering operation of the upper die 10, whereby The second slide dies 5 and 6 are moved forward and butted against each other with the butted surfaces 12a and 6a.

The butting surfaces 12a, 6 in a state where the first and second slide dies 5, 6 are butted against each other.
a is set at a position substantially orthogonal to the axis of the pilot hole preformed in the work W and the longitudinal direction of the first slide die 5, and as shown in FIG. 12a and 6a are formed with semicircular recesses 25 or 26, and the first slide die 5
The butting surface 12a on the side is formed in a V groove shape, and the butting surface 6a on the second slide die 6 side is formed in a mountain shape corresponding to the V groove shape. Therefore, when the first and second slide dies 5 and 6 abut against each other, the abutting surfaces 12a and 6a are automatically aligned with each other by the V-groove engagement. As a result, the two concave portions 25 and 26 form a perfect circle. A die hole 27 is formed.
The diameter of the die hole 27 is set in accordance with the maximum outer diameter of the burring flange portion Fb to be formed as shown in FIG.

Here, the side surfaces of the first and second slide dies 5 and 6 are provided with U-shaped guide blocks so as to be close to the inclined cam surfaces 19 and 20 as shown in FIGS. 28 is fixed, while each drive cam 23, 2
4 has a convex portion 29 that can be engaged with the guide block 28, and the positive return mechanism 30 is formed by the guide block 28 and the convex portion 29. That is, since the inclined cam surfaces 19 and 20 and the positive return mechanism 30 coexist, the first and second slide dies 5 follow the movements of the drive cams 23 and 24 when the upper die 10 is raised. , 6 are forcibly pulled back away from each other.

The lower die 9 has a plurality of lifter rods (only one is shown in FIG. 2) for lifting the processed work W from the die 3 by a stroke S ₃ .
31 are provided.

On the other hand, as shown in FIGS. 3 and 4, a solid cylindrical burring punch 32 which is arranged opposite to the above-mentioned pilot hole on the same axis with the terminal portion Q of the workpiece W to be burred. , 33 are burring punches 32, 3 respectively.
Each of the slide cams 34 and 35 is individually fixedly supported by an independent slide cam 34, 35, and each of the slide cams 34, 35 is formed with an inclined cam surface 36. In addition, each slide cam 3
4 and 35 are slidably supported by a support block 37 fixed on the lower holder 1, and are urged in a direction away from each other by a return spring 38 provided between the support block 37 and the support block 37. Further, the slide cams 34, 35 are individually provided with sectional pads 39, 40 so as to surround the burring punches 32, 33. These sectional pads 3
9 and 40 are a guide pin 41 and a liquid sealing type spring means 4.
2, the slide cams 34 and 35 are slidably supported by the slide cams 34 and 35. As described later, the work W is pressed and restrained by contacting the work W prior to the burring punches 32 and 33. become.

As shown in FIG.
Drive cams 43 each having an inclined cam surface 43a are individually provided on the upper die 10 in correspondence with the upper and lower molds 4, 35. As will be described later, these drive cams 43 are in sliding contact with the respective slide cams 34, 35. Thereby, the slide cams 34 and 35 are driven to slide. The driving system of the slide cams 34 and 35 is also provided with a positive return mechanism 46 including a guide block 44 and a convex portion 45 as shown in FIG.

The above-mentioned liquid-sealing type spring means 42
Is a type in which a predetermined liquid is sealed inside a cylinder-piston mechanism, and can exert a larger spring force than a coil spring or the like. Also, in FIG. 4, only one guide pin 41 is shown on one slide cam 34 and only a liquid sealing type spring means 42 is shown on the other slide cam 35 due to the drawing, but it is clear from FIG. To
Each of the slide cams 34 and 35 has a single guide pin 41 and two liquid-filled spring means 42 individually.

As shown in FIG. 2, the upper holder 2 has
A pad 8 for pressing and restraining the work W positioned on the die 3 from its upper surface is provided. The pad 8 is elastically supported by the upper holder 2 via a plurality of guide rods 47 and an elastic body such as a compression coil spring (not shown) so as to be able to move up and down. Pressurization is restricted.

Next, a series of operations for burring by the press die will be described.

In a state where the upper die 10 shown in FIG. 2 is waiting at the top dead center position, a work in which a pilot hole has been formed in the flange portion F of the terminal portion Q in advance in the previous process. W
Are positioned on the die 3 with reference to the locating pin 7, that is, on the locating die 4. With this positioning, the pilot hole preformed in the work W is
It is located on the same axis as the burring dies 32 and 33 waiting on the side.

When the upper die 10 is lowered after the completion of the positioning of the work W, the pad 8 first comes into contact with the upper surface of the work W and presses and restrains the work W with the locating die 4. . Further, as the upper die 10 descends, the drive cams 23 and 24
The slide dies 5 and 6 are slidably contacted with the first and second slide dies 5 and 6 while being guided by the slide dies 5 and 6.
6 move forward so as to approach each other, and finally abut on the axis of the pilot hole as shown in FIG.

At this time, the first and second slide dies 5, 6
At the time of abutting each other, both abutting surfaces 12a,
Since the semicircular recesses 25 and 26 are autonomously centered by the engagement of the V-groove 6a, the accuracy of the die hole 27, which is an important factor in burring quality, can be maintained with high accuracy. .

Thus, the first and second slide dies 5, 6
When they are abutted with each other, another drive cam 43 is inserted into each of the slide cams 34 and 35 later than this, as shown in FIG.
As a result, the slide cams 34 and 35 start to move forward in a direction approaching each other. More specifically, although the burring punches 32 and 33 integral with the slide cams 34 and 35 also move forward with the forward movements of the slide cams 34 and 35, first, the sectional pads 3 at the distal ends of the slide cams 34 and 35 first.
9 and 40 are in contact with the work W and press the end portions Q of the work W to be subjected to burring, that is, the right and left flange portions F, against the first and second slide dies 5 and 6.

Further, when the work W is restrained by the sectional pads 39 and 40, each slide cam 3 is moved.
With the forward movement of the burring punches 32,
33 is press-fitted into the die hole 27 on the die 3 side while pushing and expanding the pilot hole formed in the flange portion F. That is, the burring punches 32 and 33 and the die hole 7 cooperate with each other,
A burring hole B is formed by bending and forming the burring flange portion Fb so as to push and expand a prepared hole formed in the flange portion F of the work W in advance. 2 and 4 show the state at the moment when the upper die 10 reaches the bottom dead center position and the burring process is completed.

When the burring is completed and the upper die 10 starts to rise from the bottom dead center position again, the slide cams 34, 3
5, while the first and second slide dies 5, 6 also begin to gradually retract from the state shown in FIG. 4 in the direction away from each other. At this time, the positive return mechanism 30, 4 described above is used.
By the operation of 6, the burring punches 32 and 33 are forcibly pulled out from the burring hole B, and the first and second slide dies 5 and 6 are also forcibly pulled out from the terminal portion Q of the work W. Further, even though the burring flange portion Fb formed by the burring process interferes with the die 3 in the workpiece extracting direction, the die hole 7 directly involved in the burring process has been formed as described above. Since the first and second slide dies 5 and 6 are separated from each other, interference between the burring flange portion Fb and the die 3 can be avoided without difficulty.

When the upper mold 10 rises to near the top dead center position, the lifter rod 31 on the lower mold 9 side rises, and FIG.
Is lifted up to the lift-up position shown in (1), and the work W is carried out by a gripper (not shown), thereby completing one cycle of burring.

As described above, according to the present embodiment, the burring is performed using the burring punches 32 and 33 and the slide-divided die 3, so that the burring flange portion Fb and the die after the burring are formed. 3 can be avoided, and the periphery of the burring hole B of the work W can be sufficiently pressurized and restrained during the burring processing, so that the work W can be easily removed after the processing and the processing quality of the burring processing is improved. Will be compatible.

The preparation of the pilot hole performed in the preceding step prior to the burring processing in the present embodiment is described in FIGS.
Performed using a mold structure similar to. That is, since the piercing of the prepared hole does not cause the problem of interference at the burring flange portion Fb unlike the burring, the burring punches 32 and 33 shown in FIG. By using a button die corresponding to the pierce punch in place of 3, the preparation of the pilot hole is basically performed under the same behavior as in the present embodiment.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a press die for burring according to the present invention, and is an exploded perspective view of a main part showing a mutual relationship between a work, a slide die, and a burring punch.

FIG. 2 is a view showing the structure of a press die for burring;
FIG. 4 is a sectional view taken along the line aa in FIG. 3.

FIG. 3 is a plan view of the lower die shown in FIG. 2;

FIG. 4 is a sectional view taken along the line bb in FIG. 3;

FIG. 5 is a bottom view of the upper die shown in FIG. 2;

FIG. 6 is a view in the direction of arrow c in FIG. 2;

FIG. 7 is a view in the direction of arrow d in FIG. 2;

FIG. 8 is a view in the direction of arrow e in FIG. 4;

FIG. 9 is a view in the direction of arrow f in FIG. 4;

FIG. 10 is a perspective view of a main part of a work to be subjected to burring.

FIG. 11 is a vertical sectional view of FIG. 10;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Lower holder 2 ... Upper holder 3 ... Die 4 ... Locating die 5 ... First slide die 6 ... Second slide die 6a ... Butting surface (divided surface) 8 ... Pad 9 ... Lower die 10 ... Upper die 12a ... Butting surfaces (divided surfaces) 19, 20 ... inclined cam surfaces 23, 24 ... drive cams 23a, 24a ... inclined cam surfaces 25, 26 ... concave portions 27 ... die holes 32, 33 ... burring punches 34, 35 ... slide cams 43 ... Drive cam 43a: inclined cam surface B: burring hole E: web F: flange portion Fb: burring flange portion Q: terminal portion W: work

Claims (4)

[Claims] 1. A work having a substantially U-shaped cross section formed by a web and flange portions bent and formed so as to face each other on both sides of the web, burring holes located on the same axis with each other in each flange portion. A method of forming, wherein a flat plate-shaped material is bent into a substantially U-shaped cross-section to form a work into a predetermined shape; and Forming a pilot hole in each of the workpieces by piercing, and a dividing surface inserted into the U-shaped space of the work and substantially orthogonal to the longitudinal direction of the work and the axis of the pilot hole. Cooperating with two slide dies which can be approached and separated in the longitudinal direction of the work and a burring punch which can slide in the axial direction of the pilot hole with respect to this slide die By performing a burring process from the outside to the inside of each of the flange portions in which the pilot holes are formed, forming a burring hole by bending and molding the burring flange portion while expanding the diameter of the pilot holes, A burring method comprising: 2. A work preliminarily formed into a substantially U-shaped cross section by a web and flange portions bent and formed so as to face each other on both sides of the web, and are located on the same axis in each of the flange portions. An apparatus for forming a burring hole, wherein a work in which a lower hole is previously formed at a burring hole forming position is provided on a lower holder to form a lower die together with the lower holder, thereby releasing the U-shaped space. A die that fits inside the work and positions the work by being placed with the part facing downward, and an upper die that is elastically supported by the upper holder so as to be able to move up and down and forms the upper die And a pad that presses and constrains the work on the die by an upper mold processing operation, and the work is sandwiched between the work and the lower holder by being positioned on the extension axis of the prepared hole. Are arranged on both sides of
A pair of burring punches that form a burring hole by forming a burring hole by bending the burring flange portion while expanding the diameter of the lower hole in cooperation with the die by being cam-driven in response to the lowering operation of the upper die. In addition to a fixed locating die for positioning the work, the die is a pair of slide dies that are bisected in the longitudinal direction of the work with a vertical dividing surface passing through the axis of the prepared hole. The slide dies are formed so as to be able to approach and separate from each other, and each slide die is cam-driven in advance of the slide operation of the burring punch in accordance with the lowering operation of the lower die. The divided surfaces of the slide die are abutted on the axis of the prepared hole to form a die hole that meshes with the burring punch. Burring apparatus, characterized in that it it. 3. The slide die is formed with a concave portion corresponding to a half-shape of a die hole in a divided surface thereof, and when the two divided surfaces abut each other, a die hole is formed by these concave portions. The burring apparatus according to claim 2, wherein: 4. One of the divided surfaces of each of the slide dies is formed in a V-groove shape, and the other is formed in a mountain shape corresponding to the V-groove shape. The burring apparatus according to claim 3, wherein the burring apparatus is formed so as to exhibit a centering function.