JPH0428654Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a hemming processing device that consists of two processes: preliminary bending (referred to as pre-bending) and main bending (referred to as hemming). This invention relates to a hemming processing device that can be used for hemming.

[Conventional technology]

Hemming is performed, for example, on the entire area around a car door. Generally, such a hemming process is performed by attaching an outer panel 2 whose end portion 2a has been bent in advance on a lower die 1, as shown in FIG. 4 A, B, and C.
A first step of placing the inner panel 3 on top of the outer panel 2 and performing pre-processing in the order of A, B, and C using an upper mold 4 whose lower surface is formed into an inclined plane of about 45 degrees; As shown in (d), the hemming process is carried out in a second step in which hemming is performed using an upper die 5 whose lower surface is formed flat.

In the above pre-processing, for example, if the upper die 4 is lowered by 8 mm from the position where it contacts the upper end of the end portion 2a of the outer panel 2 to the position where the pre-processing is completed,
As the upper mold 4 descends by 3 mm from the state shown in Fig. A of the lowering amount O, it reaches the state shown in Fig. B, and further descends by 8 mm to progress to Fig. C, the pre-processing force per unit length applied to the end portion 2a increases. F changes as shown in FIG. This pre-processing force F is determined by the amount of descent of the upper mold 4 of approximately 1.3
Maximum Fsm occurs when mm. Taking the upper back side of an automobile's luggage compartment door as an example, if the end portion 2a of the outer panel 3 is pressurized at the same timing, and the entire length of the end portion 2a is L, the maximum pressure applied to the outer panel 2 is The force is L・Fsm.

[Problem that the invention attempts to solve]

Maximum load L・Fsm applied to this outer panel 2
If it becomes larger than the yield strength of the outer panel 2, distortion or deformation will occur in the outer panel 2. In order to solve this problem, as disclosed in Japanese Patent Publication No. 58-181430, the width and bending angle of the end flange 2a of the outer panel 2 are partially changed, so that the upper die 4 A method of adjusting the timing of contact with 2a has been proposed. However, changing the width of the end flange 2a of the outer panel 2 deteriorates the workability when applying sealer to the flange end after hemming, which is a later process.
There was a problem in that there were restrictions on the parts and lengths where the width could be changed. Also, when changing the bending angle of the flange, if the amount of change is large, the outer flange 2
is reversely bent, so the upper mold 4 is bent at the end flange 2a.
There was a problem in that it took a small timing difference to make contact with the object.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hemming processing device that can prevent distortion and deformation from occurring during pre-processing of an outer panel.

[Means for solving problems]

In order to achieve the above object, the present invention provides a hemming processing device that vertically lowers an upper die and hems an inner panel and an outer panel placed on a lower die using preliminary bending means and main bending means. The inclined pressing surface of the upper die for pre-bending is formed into a wave shape in the width direction, thereby preventing the occurrence of distortion and deformation during pre-processing of the outer panel.

[Effect]

According to the above configuration, since the wavy unevenness is formed on the press surface for preliminary bending of the upper mold, the convex part of the upper mold hits the bent flange end of the outer panel first, and then the upper mold The concave part of As a result, the pre-load can be dispersed, and distortion and deformation of the outer panel can be prevented.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a hemming device according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In this figure, parts that are the same or equivalent to those of the conventional example shown in FIG. 3 are denoted by the same reference numerals, and their explanation will be omitted. The feature of the present invention is the shape of the pressing surface on which the upper die 4 for pre-processing comes into contact with and presses the bent flange end 2a of the outer flange 2. This pressing surface is inclined, and the surface has a width It is formed in a wave shape in which convex portions 4a and concave portions 4b are alternately arranged in the direction.

Next, the operation of this embodiment will be explained with reference to FIGS. 1 and 2. As shown in FIG. 1, the upper mold 4 has been lowered vertically, that is, in the direction of arrow P, and is placed on the lower mold 1. The upper end of the bent flange end 2a of the outer panel 2 shown by the two-dot chain line First, the convex portion 4a of the upper mold 4 comes into contact with the mold, as shown in FIG. 2A.
Next, as shown in (b), the pre-processing of the outer panel 2 at this contact portion proceeds. As the pre-processing progresses, the processing range gradually expands, and the recess 4b of the upper die 4 also begins to come into contact with the flange end 2a of the outer panel 2, as shown in FIG. Further, the entire pre-processing progresses, and in the state shown in D, the pre-processing is completed at a predetermined angle, for example, the flange end 2a becomes a waveform of about 45 degrees.

According to this embodiment, the upper mold 4 for pre-processing comes into contact with the flange end 2a of the outer panel 2, changes the pre-processing load as the pre-processing progresses, and disperses the maximum load L・Fsm mentioned above. be able to. Therefore, pre-processing can be performed without exceeding the proof stress of the outer panel 2, and the outer panel 2
This can prevent distortion and deformation from occurring. As a result, conditions for hemming such as the shape of the outer panel 2, the length of the flange end 2a, and the bending angle are relaxed, and the cost of the press die for manufacturing the outer panel individually can be reduced. For example, when pre-processing the outer panel of an automobile's rack compartment door, the pre-processing force F can be reduced if the bending angle of the flange end due to this pre-processing is small; however, for this purpose, it is necessary to bend the end in advance. The angle must be made large, and one additional process step using a press mold is required. However, according to this embodiment, since the pre-forming force F is dispersed, the pre-forming can be performed without causing distortion or deformation of the outer panel even if the angle of the end portion to be bent in advance is small, so the press mold can be used. Type 1 or the shifting cam can be omitted.

FIG. 3 shows a second embodiment of the present invention. In this embodiment, the angle of the pressing surface of the upper die 4 for pre-processing with respect to the lower die 2 is alternately changed to α and β in the lateral direction to form a wavy shape. This embodiment also has the same effects as those of the above-mentioned embodiments, and in addition, bending can be started smoothly especially at the initial stage of pre-processing.

[Effect of idea]

As described above, according to the present invention, the pressing surface of the upper mold for pre-processing provided in the hemming processing device is formed in a waveform, so even if the upper mold comes into contact with the flange end of the outer panel, the pre-load is not applied. This has the great effect of preventing the outer panel from being distorted or deformed by being dispersed.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the main parts of an embodiment of the hemming device according to the present invention, FIG. 2 is a side view showing the processing steps by the device shown in FIG. 1, and FIG. FIG. 4 is a side view showing the working example of the embodiment, FIG. 4 is a side view showing the processing steps by a conventional hemming device, and FIG. 5 is a graph showing the relationship between the amount of lowering of the upper mold during pre-processing and the pre-pressing force. 1...Lower mold, 2...Outer panel, 3...Inner panel, 4...Upper mold, 4a...Protrusion, 4b...
recess.

Claims (1)

[Scope of utility model registration request] In a hemming device in which an upper mold is vertically lowered and an inner panel and an outer panel placed on a lower mold are hemmed by a preliminary bending means and a main bending means, the upper mold is pressed at an angle for the preliminary bending. A hemming processing device characterized by a surface formed into a waveform in the width direction.