JPH05228557A - Hemming device - Google Patents

Abstract

PURPOSE:To prevent generation of face droop and spring-back at the time of hemming. CONSTITUTION:In an inner pad 14, the guide face 141 of a shape corresponding to a flange bend tip locus of a work is formed, and at the time of hemming, the tip of a flange 3 is brought into slide-contact with the guide face 141 formed in the inner pad 14 and guided. As a result, a movement of the flange 3 to the guide face 141 side is detained and generation of face droop is prevented. Also, a raised part 16 of an angle corresponding to a flange angle of the work placed on the lower die 15 is formed on the work placing face 151 of the lower die 15, and an inner pad 6 for descending by preceding a hem edge 4 and pressing and holding the work placed on the lower die 15 is provided. In such a way, the work is pressed and fixed to the lower die 15 by the inner pad 14 first, and subsequently, the hem edge 4 descends and the flange 3 is bent, based on a bending point 7 as a reference, deformation in the spring-back direction of the bending point 7 part is detained by the raised part 16, and generation of spring-back can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a hemming processing device for preventing the occurrence of chamfering or scraping that occurs during hemming processing.

[0002]

2. Description of the Related Art For example, when processing an edge of an automobile door, the inner panel and the outer panel that form the door are overlapped with each other, and the outer panel edge (flange) is bent to form the inner panel edge. Hemming is done to wrap the part.

First, an outline of hemming will be described. As shown in FIG. 5, an inner panel (hereinafter simply referred to as “inner”) 1 and an outer panel (hereinafter simply referred to as “outer”) 2 are overlapped with each other, and a pre-blade 4 is brought into contact with the tip of a flange 3 of the outer 2 to be bent, and is obliquely downward. After pressing and bending, the hem blade 5 is lowered to further bend the flange 3, and the edge of the inner 1 is processed to be wrapped with the flange 3 of the outer 2 as shown in FIG. In this hemming process, a so-called scrape occurs in which the bending start point protrudes outward as shown in FIG. 9 (a), or the flange 3 bends off the bending point 7 as shown in FIG. Who can occur.

As described above, when surface sagging or scraping occurs, the accuracy of the external dimensions of the product deteriorates, resulting in a defective product.
In the case of weeping, the appearance of the product will be impaired.
Therefore, in the hemming process, it is a technical subject to prevent such chamfering and scraping. Therefore, as an example of the conditions for hemming that does not cause such chamfering or scraping, for example, in the case of an automobile door, when the work is set in the lower mold as shown in FIG. 5, the flange 3 of the outer 2 stands upright. Therefore, it is preferable that the flange angle α be 105 ° or less in at least FIG. 5, and the angle β between the pre-blade 4 and the flange 3 (hereinafter referred to as the pre-blade bending angle). Is required to be up to 65 °, and as shown in FIG. 6, the pre-processing completion angle γ is 35 °.
To 45 ° is required.

As a conventional means for preventing the above-mentioned chamfering and scraping, a pre-blade 4 is used by using a core metal 6 as shown in FIG.
In some cases, the flange 3 of the outer 2 is pressed against the cored bar 6 for pre-processing, and then the cored bar 6 is retracted and hemming is performed by the hem blade 5.

Further, in the one disclosed in JP-A-60-206537 (shown in FIG. 11), the work W is placed on the folding die 9 provided with the step 8 by utilizing the elastic force of the spring 10 and the flange punch 11. Then, the flange of the work W is inclined at an appropriate angle in the bending direction like 13 'by a suitable means, and then the folding punch 12 is lowered to perform hemming between the step 8 and the flange punch 11. With
The flange 13 is formed on the side surface of the flange punch 11. In addition, Japanese Utility Model Laid-Open No. 3-57421 discloses an apparatus for pressing and fixing a work to a lower mold at an upper mold end, and lowering a hem blade provided at an end of the upper mold so as to be vertically movable to perform a hemming process. ing.

[0007]

In the above conventional example,
First, in the case of using a core metal, if the pre-blade is pressed hard against the core metal during pre-processing, the core metal will bend and escape if the strength of the core metal is insufficient, so the bending point of the flange will shift As a result, there is a problem that surface sagging occurs, and there is a problem that the pre-processing completion angle γ cannot be set to 45 ° or less and defective products may occur. It is also possible to make the core metal large in order to make the core metal sufficiently strong, but the core metal must be retracted when hemming. Therefore, if the cored bar is enlarged, the space for retracting the cored bar cannot be taken, and there is a certain limit to prevent the cored bar from being bent by enlarging it.Therefore, this method using the cored bar causes chamfering. The problem is that there is always the potential to do so.

Next, in both the hemming processes disclosed in JP-A-60-206537 and Japanese Utility Model Laid-Open No. 3-57421, the work is pressed and fixed to the lower mold to perform the hemming process. Although it does not occur, since there is no support for the bending point of the flange portion, there is a problem that sagging occurs. In particular, in the one disclosed in Japanese Patent Laid-Open No. 60-206537, the hemming process is performed so as to be restrained between the step 8 and the side surface of the flange punch 11, so that it is considered that there is no chamfering. However, since the height of the step 8 is high, there is nothing that restrains the bending point of the workpiece when pre-machined like the flange 13 ', and the position of the bending point is not constant, and Since the side surface of the flange punch 11 is a vertical surface, the edge of the flange is bent like the flange 13, and even if the edge of the flange is pressed against the vertical surface of the flange punch 11, this pressing force is not applied. Who does not work to straighten.

The present invention provides a hemming device that does not cause chamfering or scraping.

[0010]

Means for Solving the Problems According to the present invention for solving the above-mentioned problems, a flange of a work is applied to a core metal and bent by a pre-blade at a predetermined angle, and then the flange is further hem-bladed. In a hemming processing device for bending an edge of a work by bending the work, the stopper surface supporting the bending point is provided at a portion corresponding to the bending point of the flange of the work placed on the lower die on which the work is placed. A raised portion is formed on the work mounting surface of the lower die, and the inner pad that presses down and holds the work placed on the lower die by descending prior to the hem blade is used as a bending locus of the flange tip of the work. It is characterized in that a guide surface having a corresponding shape is formed.

[0011]

Since the present invention is constructed in this way, it has the following actions. That is, even if the pre-blade is pressed against the core metal of the flange of the work and the flange is bent at a predetermined angle, the pressing force of the pre-blade is received by the lower die and the core metal does not bend. Since the core metal does not bend in this way, it is possible to make the core metal small to make a sufficient retreat space to achieve a predetermined pre-processing completion angle γ, and to use a flange that is pressed and bent by the pre-blade. The position of the bending point is fixed by the core metal. Then, when the flange is bent by the hem blade, the work is supported by the lower mold and the bending point is formed at a fixed position, so that the flange can be bent with reference to this bending point. In this way, by bending the flange based on the bending point, the trajectory of the flange tip draws an arc centered on this bending point and having a radius of the flange length. It moves by being slidably guided by the guide surface formed on the pad, and the movement of the flange toward the guide surface is restricted, so that it is possible to prevent the occurrence of chamfering.

On the other hand, a ridge having an angle corresponding to the flange angle of the workpiece placed on the lower die is formed on the workpiece placing surface of the lower die, and is lowered before the hem blade and placed on the lower die. Since the inner pad that holds the work being pressed is provided, the work placed on the lower mold is first pressed and fixed to the lower mold by the inner pad, and then the hem blade descends and the bending point is used as a reference. The flange is bent, the tip of the flange slides on the guide surface formed on the inner pad and moves, and the bending point part is closely fixed to the ridge of the angle corresponding to the flange angle, It is possible to restrain the bending point portion from deforming in the shakure direction by the raised portion.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. In FIG. 1, which shows a state in which the hem processing is performed in a vertical section, the hem blade 5 is fixed to an upper mold (not shown), and is slidable with respect to the hem blade 5 via a spring 17. The inner pad 14 is attached to an upper mold (not shown). Reference numeral 15 denotes a lower mold having a mounting surface 151 on which the outer 2 is mounted, and the mounting surface 151 of the lower mold 15 has a raised portion 16 having an angle corresponding to the flange angle α of the outer 2 (see FIG. 5).
Are formed.

In FIG. 2, which shows a longitudinal section of the pre-processed state, the bending point 7 is located on the mounting surface of the lower die 15.
The inner 1 and the outer 2 are placed on the 151 in an overlapping manner on the extension line 101 of the upper surface of the inner 1 and the pre-processed surface 601 of the cored bar 6 is formed so that the corner is located at this bending point 7. The bottom surface 602 is formed so as to be in close contact with the inner 1 and the bottom surface 603 is formed so as to be adhered to the outer 2 respectively. When the flange 3 is sandwiched between the pre-processed surface 601 of the cored bar 6 and the pre-processed surface 401 of the pre-blade 4, the extension H of the pre-processed surface 401 of the pre-blade 4 is It is determined as an intersection that intersects the sliding surface 17 between the blade 4 and the lower die 15. The angle between the mounting surface 151 of the lower mold 15 and the raised portion 16 is equal to the flange angle of the outer 2.

In FIG. 3, which shows the state immediately before hemming in a longitudinal section, a guide surface 141 is formed on the inner pad 14, and the guide surface 141 is formed at the bending point 7 of the flange 3.
Centered at, and the length R from the bending point 7 of the flange 3 to the tip
It has an arc shape with a radius of (flange length). That is, the shape of the guide surface 141 is such that the flange 3 has the bending point 7
Is a surface that is equal to the trajectory drawn by the tip of the flange 3 when bent with respect to. In addition, as shown in FIG. 2, the flange 3 starts when the guide surface 141 starts.
When the pre-processing complete angle γ when pre-processing by the pre-processing surface 601 of and the pre-processing surface 401 of the pre-blade 4 is reached,
It is determined that the tip of the flange 3 starts to slide on the guide surface 141.

The operation of the present embodiment configured as described above will be described below. Referring to FIG. 4 showing the hemming process, first, in the process (a), the mounting surface 151 of the lower mold 15 with the inner 1 overlaid on the outer 2 bent at the flange angle α.
Placed on. In this process, the mounting surface 151 and the ridge
Since the angle between the outer surface 2 and the flange 16 is equal to the flange angle α, the outer 2 is mounted in close contact with the mounting surface 151 and the raised portion 16.

Next, in the step (b), the upper mold (not shown) is lowered to move the cored bar 6 in the direction of the arrow to press and fix the inner 1 and the outer 2 to the mounting surface 151, and at the same time, to fix the outer 2 The bent portion is fixed so as to be pressed against the raised portion 16. Then, the pre-blade 4 is moved in the direction of the arrow so that the flange 3 is sandwiched between the pre-machined surface 601 of the core metal 6 and the pre-machined surface 401 of the pre-blade 4 for pre-machining. In this pre-processing, the pressing force of the pre-blade 4 is transmitted to the cored bar 6 via the flange 3, but the component force of the force applied to the cored bar 6 is received by the lower die 15, so that the cored bar 6 is not deformed (flexed). Restrained by the lower mold 15.

This makes it possible to reduce the size of the cored bar 6 and secure a retreat space for the cored bar 6. Therefore, in the retreat of the cored bar 6 in the hemming which is the next step, the degree of freedom in the retreat direction is expanded, and the pre-machining completion angle γ can be set to 45 ° or less. Further, since the bending of the cored bar 6 is restrained by the lower die 15 in this way, the pre-processed surface of the cored bar 6
The corners of 601 are fixed at a fixed position, and the bending point 7 of the flange 3 is formed at a fixed position. Further, when the position of the bending point 7 and the height H of the raised portion 16 are configured as described with reference to FIG. 2, the flange 3 includes the raised portion 16 and the core metal 6.
Since it is sandwiched and bent without any play between the end of the flange 3 and the pre-processed surfaces 601 and 402, the bending point 7 is further strengthened and the flange 3 of the flange 3 with the bending point 7 as a reference is formed. Bending becomes more reliable.

Next, when the upper mold not shown is lowered, the core metal 6
Is withdrawn along the pre-machining completion angle γ (see FIG. 6) as shown by the arrow, and the inner pad 14 is lowered prior to the hem blade 5 as shown in the step (c), and the inner 1 and the outer 2 are moved.
Is fixed so as to be pressed against the mounting surface 151 by the elastic force of the spring 17 via the inner pad 14. As described above, in a state where the inner pad 14 fixes the inner 1 and the outer 2, the end portion of the flange 3 pre-processed in the step (b) is brought into sliding contact with the guide surface 141 formed on the inner pad 14. Then, when the upper die is continuously lowered, the hem blade 5 is lowered while pressing the spring 17 by the upper die to hemm the flange 3.

In this hemming, the bending point 7 is (b)
Since it is formed at a fixed position in the process of, the flange 3
The center point of the circular arc where the tip of the arc moves around this bending point 7 in an arc, and the central point of the guide surface 141 that is formed with the length R of the flange 3 as the radius around the bending point 7. It is in a substantially aligned state, and the tip of the flange 3 is guided while being in sliding contact with the guide surface 141.

Therefore, even if the flange 3 moves toward the guide surface 141 side during hemming (the bending portion is in the direction of the chamfer), the movement is restricted by the guide surface 141. On the other hand, since the raised portion 16 is provided on the mounting surface 151 at the same angle as the flange angle α of the outer 2, the outer 2 is placed in close contact with the mounting surface 151 and the raised portion 16, and the hem is attached. Deformation of the outer 2 in the shakure direction during processing is due to the raised portion 16
And the mounting surface 151. In this way, the flange 3 is hemmed without shading and chamfering, as shown in (d), while the guide surface 141 prevents chamfering and the mounting surface 151 and the raised portion 16 prevent shading.
Also, in this way, the guide surface 141 prevents surface sagging and the mounting surface.
The prevention of scraping by the 151 and the raised portion 16 enables hemming without scraping or chamfering even if the condition 35 ° ≦ γ ≦ 45 ° of the pre-processing completion angle γ is not satisfied to some extent.

[0022]

As described in detail above, according to the present invention, the pressing force of the pre-blade is received by the lower die, and the core metal does not bend. Therefore, it is possible to make the core metal small so that there is a degree of freedom in the direction of the retreat direction, and since there is no bending of the core metal, the pre-processing completion angle γ can be set to a predetermined angle and at a fixed position. It is possible to form the bending point of the flange on the. As a result, the flange is bent on the basis of this bending point, and a guide surface having a shape corresponding to the trajectory of the flange bending tip of the work is formed on the inner pad, so that the tip of the flange is formed on the inner pad. It is possible to prevent the occurrence of surface sag by restraining the movement of the flange toward the guide surface side while being guided by sliding contact with the surface and moving.

Further, a ridge having an angle corresponding to the flange angle of the workpiece placed on the lower die is formed on the workpiece placing surface of the lower die, and is lowered before the hem blade and placed on the lower die. Since an inner pad for pressing and holding the workpiece is provided, the workpiece placed on the lower die is first pressed and fixed to the lower die by the inner pad, and then the hem blade descends and the bending point is used as a reference. The flange is bent, and the tip of the flange moves in sliding contact with the guide surface formed on the inner pad, and the bending point portion is fixed in close contact with the ridge having an angle corresponding to the flange angle. It is possible to prevent the crease from occurring by restraining the bending point portion from deforming in the crease direction by the raised portion.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention showing a state of hemming.

FIG. 2 is a vertical sectional view of one embodiment of the present invention showing a pre-processed state.

FIG. 3 is a vertical cross-sectional view of an embodiment of the present invention showing a state immediately before hemming.

FIG. 4 is a diagram showing a hemming process of the present invention.

FIG. 5 is an explanatory diagram of a hemming process.

FIG. 6 is an explanatory diagram of a hemming process.

FIG. 7 is an explanatory diagram of a hemming process.

FIG. 8 is an explanatory diagram of a hemming process.

FIG. 9 is an explanatory diagram of a hemming process.

FIG. 10 is an explanatory diagram of hemming processing.

FIG. 11 is a vertical cross-sectional view of a conventional example.

[Explanation of sign]

 1 Inner 2 Outer 3 Flange 4 Pre-blade 5 Hem blade 6 Core bar 7 Bending point 14 Inner pad 141 Guide surface 15 Lower mold 151 Mounting surface 16 Raised part

Claims (1)

[Claims] 1. A hemming processing apparatus for processing a flange of a work by applying a flange of the work to a core metal and bending it at a predetermined angle with a pre-blade, and then bending the flange with a hem blade to process the edge of the work. A ridge having a stopper surface for supporting a bending point of a flange of a workpiece placed on the lower die to be placed is formed on the workpiece placing surface of the lower die, and the hem blade is formed. A hemming apparatus, wherein a guide surface having a shape corresponding to a bending locus of the flange tip of the work is formed on the inner pad that descends prior to and presses and holds the work placed on the lower die.