JPH08103835A - Hemming device - Google Patents

Abstract

PURPOSE: To provide a hemming device by which a pair of metal sheets is surely firmly worked in a hemming process with the minimum man-hour. CONSTITUTION: The device is such that the edge 1a of a first metal sheet 1 is placed with the edge 2a of a second metal sheet 2 superposed on a lower die 5, that the hem flange 1b at the tip end of the edge 1a of the first metal sheet 1 is folded back over the edge 2a of the second metal sheet 2, and that the hem flange 1b is pressed on the edge 2a of the second metal sheet 2 with an upper die 7 for hemming. A projection 8 is formed on the lower face of the upper die 7, the hem flange lb is partially bitten in the edge 1a of the second metal sheet 2 by the use of this projection 8, and a projected-recessed engaging part 4 is formed on the joined face with both edges. With this projected-recessed engaging part 4, a joined strength is increased in the direction parallel to the face of the joined part 3 that is hem-processed on the pair of metal sheets 1, 2, dispensing with a cure process or a weld process after hemming.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hemming device for joining edge portions of a pair of sheet metals constituting an outer panel body of an automobile by hemming.

[0002]

2. Description of the Related Art In an outer panel body which is a sheet metal component such as an automobile hood, fender, side door, etc., generally, the outer panel and inner panel edges of the sheet metal are joined by hemming. As shown in FIG. 4, the edge portions of the first sheet metal 1 of the outer panel and the second sheet metal 2 of the inner panel, which form the outer panel body of the automobile, are joined by hemming. In this case, the flat edge 2a of the second sheet metal 2 is superposed on the flat and straight edge 1a of the first sheet metal 1, and the hem flange 1b bent at the tip of the edge 1a of the first sheet metal 1 The pair of sheet metals 1 and 2 are coupled to each other by folding the sheet metal 2 onto the edge portion 2a and pressing it.

Sheet metal joining by hemming as shown in FIG. 4 is performed as follows by using a lower die 5, a pre-bending die 6 and an upper die 7 of a hemming apparatus as shown in FIGS. 5 (a) to 5 (c). Has been done in. As shown in FIG. 5 (a), the edge 1 a of the first sheet metal 1 and the edge 2 a of the second sheet metal 2 are placed on the horizontal lower die 5 so as to overlap each other. A hem flange 1b bent upward is formed at the tip of the edge 1a of the first sheet metal 1.
The tip of the edge 2a of the second sheet metal 2 approaches or abuts the bent base end of b.

Next, as shown in FIG. 5 (b), a pre-bending die 6 is pressed obliquely against the outer surface of the hem flange 1b of the first sheet metal 1 to move the hem flange 1b above the edge 2a of the second sheet metal 2. Pre-bend at a predetermined angle. The pre-bending die 6 is removed from the pre-bent hem flange 1b, and next,
As shown in FIG. 5 (c), the upper die 7 is lowered from directly above the pre-bent hem flange 1 b, and the hem flange 1 b is further bent by the upper die 7 to be placed on the edge 2 a of the second sheet metal 2. Press. By this press, the hemming process by the lower die 5 and the upper die 7 of each sheet metal 1, 2 is completed, the upper die 7 is lifted, and the sheet metals 1, 2 joined by the hemming process are taken out from the lower die 5. It is sent to the next process.

[0005]

As shown in FIG. 4, the joining strength of the joining portion 3 of the pair of sheet metals 1 and 2 joined by the hemming process is largely stable in the Z direction of the sheet metal sheet thickness direction. When the sheet metal 1 and 2 are weak in the X and Y directions parallel to the edges 1a and 2a of the edges 1 and 2 and a relative external force acts on the sheet metal 1 and 2 in the X and Y directions, the sheet metal 1 and 2 relatively move in that direction. There is a case that the position is misaligned.

Therefore, conventionally, in order to prevent relative displacement of the joint portion of a pair of hemmed sheet metals, the hemmed sheet metal is sent to a curing step or a welding step, and the hemmed joint portion is sent. Is being reinforced. For example, after applying a thermosetting adhesive to the hemmed edges of a pair of sheet metals, the sheet metal is sent to a curing step after the hemming process, and the hemmed joints are heated by high frequency to generate an adhesive. Is cured, and the strength of the joint portion in the joint surface direction is secured by an adhesive. Alternatively, after hemming the edges of the pair of sheet metals, it is sent to a welding step to partially spot-weld the hemmed joints to ensure the strength of the joints in the joint surface direction. .

However, in the curing process and the welding process after the sheet metal hemming process, the total number of sheet metal hemming processes is increased to make it difficult to improve the workability of the sheet metal structure manufacturing. In addition, equipment for the curing and welding processes after hemming and sheet metal transportation equipment from the hemming process to the curing and welding processes are required, increasing the equipment cost of the entire sheet metal hemming device and increasing the installation space. There was a problem that needed a big one.

An object of the present invention is to hem the pair of sheet metal members securely and firmly by a single hemming process, thereby eliminating the need for a post process for reinforcing the hemmed joint part later. To provide a processing device.

[0009]

According to the present invention, a flat edge portion of a first sheet metal and a flat edge portion of a second sheet metal are superposed on the lower edge of a lower die, and the flat edge portion of the first sheet metal is moved upward from the tip. The folded hem flange is folded back onto the edge of the second sheet metal by the lowering of the upper die and polymerized, and the first sheet metal, the edge of the second sheet metal and the hem flange of the first sheet metal are pressed by the lower die and the upper die. A hemming processing device for joining by joining the hem flange of the first sheet metal to the edge of the second sheet metal by the upper die on the lower surface of the upper die and partially denting the edge of the second sheet metal. By forming a protrusion that partially engages the hem flange and the edge portion of the second sheet metal, the above object is achieved.

Further, in the present invention, it is preferable in manufacturing the upper mold that the projection on the lower surface of the upper mold is composed of the inverted conical tip of the mechanical clinch punch embedded in the upper mold.

[0011]

Operation: The edge of the second sheet metal is overlaid on the edge of the first sheet metal, the hem flange of the first sheet metal is overlaid on the edge of the second sheet metal, and these three layers are pressed by the lower die and the upper die. When hemming,
The protrusion on the lower surface of the upper mold partially dents the hem flange of the first sheet metal and the edge of the second sheet metal, and the concave and convex engaging portions are formed by the concave portions of both. With this concave-convex engagement portion, the bonding strength in the direction parallel to the bonding surface of the bonding portion between the edge portions of the first sheet metal and the second sheet metal increases, and the curing step or the welding step after the hemming processing of the sheet metal bonding portion. Post-processing steps such as the above become unnecessary.

Further, the upper mold projection partially dents the hem flange of the first sheet metal and the edge portion of the second sheet metal, but does not deform the outer surface of the edge portion of the first sheet metal. There is no change in the appearance of the edge before and after hemming.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to FIGS. The embodiment shown in the figure is applied to the hemming apparatus for the first sheet metal 1 and the second sheet metal 2 in FIG. 4, and the same or corresponding parts are denoted by the same reference symbols throughout the drawings.

As shown in FIGS. 1 and 3, the present invention is characterized in that a protrusion 8 is partially formed on the lower surface of the upper mold 7. The protrusion 8 has, for example, an inverted conical shape, and is configured by an inverted conical tip portion of a mechanical clinch punch 10 fitted in vertical holes 9 formed in a plurality of longitudinal positions on the lower surface of the upper die 7.

FIG. 1 (a) shows a stage in which the hem flange 1b of the first sheet metal 1 is pre-bent in the steps of FIGS. 5 (a) and 5 (b). From the position directly above the pre-bent hem flange 1b. The upper mold 7 descends, and as shown in FIG.
The upper die 7 further bends the hem flange 1b and presses it on the edge portion 2a of the second sheet metal 2, and the lower die 5 and the upper die 7 of each sheet metal 1, 2 are pressed.
Hemming processing by is completed.

At the time of pressing as shown in FIG. 1 (b), the protrusion 8 of the upper die 7 partially cuts into the hem flange 1b of the first sheet metal 1,
A partial depression is formed on the upper surface of the hem flange 1b and a convex portion is formed on the lower surface of the hem flange 1b opposite to the concave portion, and the convex portion partially cuts into the upper surface of the edge portion 1a of the second sheet metal 2 to form the edge portion 1a. Form a recess on the upper surface. At this time, the convex-concave portion on the lower surface of the hem flange 1b and the concave-convex engaging portion 4 due to the concave portion on the upper surface of the edge portion 1a of the second sheet metal 2 form a pair of sheet metals 1 and 2 as shown in FIGS. 2 (a) and 2 (b). The bonding strength in the X and Y directions parallel to the bonding surface of the hemmed bonding portion 3 is increased. In other words, the protrusion 8 of the upper mold 7 is formed so as to form the concave-convex engaging portion 4 having the engaging strength that increases the joint strength in the X and Y directions of the joint portion 3 of the pair of sheet metals 1 and 2. The size, shape, and number of are set.

Further, the protrusion length of the projection 8 from the lower surface of the upper die 7 is increased so that the upper surface of the edge portion 1a of the first sheet metal 1 directly below the concave-convex engaging portion 4 formed at the time of pressing in FIG. 1B. It is also possible to form a partial recess and to form a concave-convex engaging portion (not shown) also on the coupling surface of the edge portions 1a, 2a of the pair of sheet metals 1, 2. In this case, the bond strength in the X direction and the Y direction of the connecting portion 3 is further increased.

Further, since the lower surface of the edge portion 1a of the first sheet metal 1 is in contact with the flat upper surface of the lower die 5 during pressing in FIG. 1 (b), the upper surface of the edge portion 1a of the first sheet metal 1 is pressed. Even if is slightly recessed by the protrusion 8, the lower surface of the edge portion 1a is not deformed. Therefore,
When the first sheet metal 1 is the outer panel of the outer panel body of the automobile, the appearance of the peripheral edge portion does not change before and after the hemming process, which is advantageous in the subsequent coating process and the like.

By forming the protrusion 8 of the upper die 7 at the tip of the mechanical clinch punch 10 as in the above embodiment, the protrusion 8 is made to have a higher hardness than the upper die 7, and the unevenness of the hard metal plate is obtained. It becomes easy to ensure that the combination is performed. Further, by forming the protrusion 8 with the punch 10,
It suffices to form the vertical hole 9 into which the punch 10 is fitted in the upper mold 7, and the upper mold can be easily manufactured.

The present invention is not limited to the above embodiment, but depending on the type of a pair of sheet metals, a projection may be integrally formed on the lower surface of the upper die, or another projection may be fixed to the lower surface of the upper die. Is also applicable.

[0021]

According to the present invention, when the edge portions of the first sheet metal and the second sheet metal are hemmed by the press of the lower die and the upper die,
The protrusion on the lower surface of the upper mold partially dents the hem flange of the first sheet metal and the edge of the second sheet metal to form a partial concave-convex engaging portion on the joining surface of the hem flange and the edge of the second sheet metal. The concave-convex engaging portion increases the bonding strength in the direction parallel to the bonding surface of the bonding portion between the edges of the first sheet metal and the second sheet metal. Therefore, a post-treatment process such as a curing process or a welding process after the hemming of the pair of sheet metal joints is unnecessary, and the workability of the sheet metal hemming process is improved by that much, and the equipment of the hemming device is reduced in size and low in cost. Cost reduction can be realized.

Further, although the upper die projection partially dents the hem flange of the first sheet metal and the edge portion of the second sheet metal, it does not deform the outer surface of the edge portion of the first sheet metal. The appearance of the edge does not change before and after hemming, which is convenient for sheet metal painting.

Further, by forming the protrusion of the upper die at the tip of the mechanical clinch punch embedded in the upper die, various hardness of the protrusion can be easily selected, and hemming of various kinds of sheet metal is possible. A hemming processing device having excellent versatility can be provided.

[Brief description of drawings]

1A is a cross-sectional view before hemming, showing a hemming apparatus according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view immediately after hemming.

2A is a cross-sectional view of a sheet metal hemmed by the apparatus in FIG. 1, and FIG. 2B is a cross-sectional view taken along the line AA in FIG.

FIG. 3 is a partial front view of an upper die of the apparatus shown in FIG.

FIG. 4 is a partial perspective view of a hemmed sheet metal.

5A to 5C are cross-sectional views of respective steps of a conventional apparatus for hemming the sheet metal of FIG. 4, where FIG. 5A is a cross-sectional view before pre-bending,
(B) is a cross-sectional view during pre-bending, and (c) is a cross-sectional view immediately after hemming.

[Explanation of symbols]

 1 1st sheet metal (outer panel) 2 2nd sheet metal (inner panel) 3 Joining part 4 Concavo-convex engaging part 5 Lower mold 7 Upper mold 8 Protrusion 10 Mechanical clinch punch

Claims (2)

[Claims] 1. A flat edge of a first sheet metal and a flat edge of a second sheet metal are stacked on the lower die, and a hem flange bent upward from the tip of the edge of the first sheet metal is placed on the lower die. It is a hemming processing device that folds back onto the edge of the second sheet metal as the mold descends and polymerizes, and presses the first sheet metal, the edge of the second sheet metal and the hem flange of the first sheet metal with the lower die and the upper die. When pressing the hem flange of the first sheet metal to the edge of the second sheet metal on the lower surface of the upper die, the hem flange and the edge of the second sheet metal are partially recessed, and the hem flange and the second sheet metal edge are A hemming processing device, characterized in that a protrusion for partially engaging the portion with the concave and convex portions is formed. 2. The hemming apparatus according to claim 1, wherein the projection on the lower surface of the upper die is an inverted conical tip portion of a mechanical clinch punch embedded in the upper die.