JPH02112845A - Working method for axis-like projection formed by press forming - Google Patents

Abstract

PURPOSE:To forme the axis-like projection by press forming and to reduce the manufacturing cost by extruding a material of quantity required for forming an axis-like projection from a plate by using an excluding punch and thereafter, forming it to a prescribed shape dimension by using a forming punch. CONSTITUTION:In the former-process, while stretching a material of a plate 3 by a main part 11a of a punch 1a, it is extruded, and finally the material of the periphery is further extruded by a large diameter part 12, a shell-shaped projecting part 41a is formed, and also, a recessed stage part 42a is formed on the rear side, In the next process, a projection 4a formed in the preceding- process is spread out mainly in the diametral direction by a main part 11b of a punch 1b to form the projection 4b and a roughly inner cylindrical project ing part 41b corresponding to the main part 11b and a recessed stage part 42b of the rear side are formed. Subsequently, in the final process, the projection 4b is formed so as to become prescribed outside diameter and height by a main part 11c of a punch 1c to form an axis-like projection 4, and an axis-like projection of a prescribed dimension and a recessed stage part 42c of the rear side are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a processing method for forming shaft-shaped protrusions at predetermined locations on a plate material by press forming.

<Conventional technology> It is an extremely common processing method to produce various parts by pressing metal plates, and it is also possible to form burrings or cylindrical protrusions without an open top end by drawing. It is. However, in the case of protrusions that require high precision and a relatively large protrusion height, such as the shafts of levers and links, the fluidity of the material may be insufficient and cuts may occur at the rising part or upper end, or In many cases, a sufficiently satisfactory finish cannot be obtained by drawing, such as a relatively large radius being generated in the part, and conventionally, it has been common practice to fix another shaft part by caulking or the like.

<Problems to be Solved by the Invention> As described above, in the past, since separate parts were fixed, there was a problem that the number of parts and man-hours required to manufacture the parts increased, resulting in higher costs.

The present invention has been made to address these problems and to reduce costs by making it possible to form shaft-shaped protrusions by press molding.

Means for Solving the Problem> In order to achieve the above-mentioned object, the method for processing a shaft-like protrusion of the present invention uses an extrusion punch having a large-sized portion around the base in a pre-process to form a shaft-like projection. The amount of material necessary to form the protrusion is extruded from the plate material, and the extruded portion from the plate material is formed into a predetermined shape and size using a forming punch in a subsequent process.

By extruding in the above-mentioned pre-process, a concave step corresponding to the large dimension of the extrusion punch is formed on the back side of the plate material. It is desirable to select the shape and dimensions.

Further, it is desirable that the height at which the material is extruded in the previous step is equal to or greater than the height of the shaft-like protrusion to be formed.

Effects> According to the processing method of the present invention, the amount of material required for forming the shaft-shaped protrusion is extruded from the plate material in the previous step, so that there is no possibility of cuts due to insufficient material during forming in the subsequent step. Never happened.

In addition, due to the concave step formed by the large part of the extrusion punch, the extruded part and the surrounding material are separated by a constriction, which prevents material from gathering from the surrounding area during molding in the subsequent process. There are no wrinkles or distortions that tend to occur during drawing. Due to these comprehensive actions, the subsequent forming process is carried out without any problems, and the shaft-like protrusion is pressed with the same precision as when another shaft part is fixed]
It can be obtained by two things.

If the shape and dimensions of the punch are selected so that the inner dimension of the recessed step is larger than the outer dimension of the shaft-like projection.

It becomes easy to extrude the required amount of material in the previous process.

Further, when the height at which the material is extruded in the pre-process is set to be equal to or higher than the height of the shaft-like projection, it becomes easy to finish the material with a predetermined accuracy without any difficulty during molding in the post-process.

The present invention can be applied not only to cylindrical protrusions with a circular cross section as described in the following embodiments, but also to machining irregularly shaped protrusions such as prismatic protrusions, with the same high precision as in the case of cylindrical protrusions. processing is possible.

<Example> Fig. 1 is an explanatory diagram of the machining process in one embodiment, Fig. 2 is a cross-sectional view of an example of a formed shaft-shaped protrusion, and Fig. 3 is a perspective view of the main part of an example of the part after processing. be. In this example, since the shaft-like projection is cylindrical, the explanation will be made by describing the large dimension part of the extrusion punch, the outer dimension of the shaft-like projection, and the inner dimension of the recessed step part as the large diameter part, outer diameter, and diameter, respectively. It is.

In FIG. 1, (a) is a pre-process, and (b) and (c) are post-processes, and these steps are performed sequentially, for example, by continuous punching of a hoop material. In the figure, 1a is an extrusion punch, 1b, 1c are molding punches, 2a, 2b,
2c is a die type, 3 is a plate material.

4a and 4b indicate protrusions during processing, and 4 indicates a shaft-like protrusion after processing, respectively. Note that although the punch is on the bottom and the die is on the top in the figure, the top and bottom may be reversed during actual processing.

The tip of the extrusion punch 1a used in the previous step has a shape in which a large diameter portion 12a is formed at the base of a bullet-shaped main portion 11a that is tapered in a gentle arc from the middle of the cylinder. The die 2a is composed of a fixed die 21a corresponding to the main part 11a of the extrusion punch la and a movable die 22a, and the movable die 22a is supported by a spring 23a.

The plate material 3 is processed between the punch 1a and the die 2a to form protrusions 4a. In this process, first, the main part 11a of the punch 1a stretches and extrudes the material of the plate 3, and finally, the large diameter part 12a further extrudes the surrounding material to form a bullet-shaped protrusion 41a. At the same time, a recessed step portion 42a is formed on the back side.

In FIG. 1(b), which is the first stage of the post-process, the forming punch 1
The tip of b has a shape in which a large diameter portion 12b is formed at the base of a rounded cylindrical main portion 11b. The die mold 2b is composed of a fixed die 21b and a movable die 22b supported by a spring 23b.

In this step, the protrusion 4a formed in the previous step is removed by the punch 1.
The protrusion 4b is mainly expanded in the diameter direction by the main part 11b of the main part 11b, and a substantially cylindrical protrusion 41b corresponding to the main part 11b and a recessed step part 42b on the back side are formed.

Next, in the last step (C) of FIG. 1, the tip of the forming punch 1c has a cylindrical main part 11c with almost no roundness.
The die mold 2c is composed of a fixed die 21C and a movable die 22c supported by a spring 23c.
c is fixed at a predetermined position depending on the height of the shaft-shaped projection 4.

In this step, the protrusion 4b, which has become almost cylindrical in the previous step, is shaped to have a predetermined outer diameter and height by the main part of the punch IC, and becomes a shaft-like projection 4, which has a predetermined size. 41c and a recessed stepped portion 42c on the back side are formed.

As mentioned above, in this example, the machining is performed in three steps, but this is because it is easier and allows for high-precision machining than if the post-process is one step and the finished product is finished all at once.
In the case of a material with a good drawing ratio or the height of the shaft-like protrusion 4 being small, it is also possible to reduce the post-process to one process. Note that it is desirable to avoid increasing the number of steps more than necessary from the viewpoint of work hardening.

For each punch used in the above three steps, the shape and dimensions of each main part and large diameter part are selected so that a shaft-shaped protrusion 4 of a predetermined size can be obtained. According to experiments, the heights of the tips are H□, H2, and H□, and the diameters of the large diameter parts are D, D2, and D, respectively, as shown in the figure.

If the heights are dl, d2, d, and the outer diameter of the shaft-shaped protrusion 4 is D, then H > H, > H2 D = D, = D, ) D d = d, <d .

The best results were obtained when

Here, it is reasonable to make Hl the largest because it is better to extrude the material above the height of the shaft-like protrusion 4 in the pre-process and place it at -C, which eliminates the need to further stretch the material during molding in the post-process. It is effective in making molding possible, and H3
It is considered that making H2 larger than H2 is effective in finishing the height of the shaft-shaped protrusion 4 with a predetermined accuracy.

In addition, making the diameter of each large diameter part larger than the outer diameter of the shaft-like protrusion 4 is to prevent the height of the large diameter part from being larger than necessary relative to the thickness of the plate material and to reduce the extrusion of the material in the previous process. It is effective in increasing the size of the extruded part and making it possible to perform subsequent molding without difficulty, and it is also effective in keeping the extruded part and the surrounding material in a separated state. Conceivable.

Further, it is considered that making d larger than the others is effective in increasing the pressing force by the large diameter portion 12c of the punch 1c and improving finishing accuracy.

Regarding each die type, there is no particular difference except that the movable die 22c of the die type 2c is fixed at a predetermined position according to the height of the shaft-like projection 4, and those of the same shape and size can be used. It is.

The specific dimensions of each punch are based on the material and thickness of the plate,
Although it cannot be specified because it is selected for each individual case according to the outer diameter, height, etc. of the shaft-like projection, an example of the dimensions of the shaft-like projection is as follows.

That is, if the dimensions of each part are indicated by symbols as shown in Fig. 2, the height of the shaft-shaped protrusion 4 is H = 3, 0 n town outer diameter for an electrogalvanized steel plate with a plate thickness of t = 1, 6 nn. D” 3
, 0 on+ inner diameter, = 2.4+ diameter of field concave stepped portion 42c. = 3, 6 n.

Depth d = 0, 7 nIT.

Such processing could be easily carried out by this invention. Note that the rising portion 5 has almost no radius, and a shaft portion similar to that obtained by caulking separate parts is obtained.

FIG. 3 shows the part of the processed part 6 where the shaft-like protrusion 4 is provided. For example, by continuous punching of the plate material 3, in addition to forming the shaft-like protrusion 4, necessary drilling, bending, etc. Finally, outline cutting is performed to produce the part 6. In the case of this invention, unlike the general drawing process, almost no internal stress is generated in the plate material surrounding the shaft-like protrusion 4, so as shown in the figure, the narrow part 6 of the part 6
Even if the shaft-shaped protrusion 4 is provided on a, the plate material will not be distorted, and the precision of the entire component will be improved.

<Effects of the Invention> As is clear from the above-mentioned embodiments, the method of processing shaft-shaped protrusions by press forming of the present invention involves extruding the necessary material from the plate material using an extrusion punch having a large-sized portion around the base. Thereafter, the extruded portion is molded to a predetermined external size to obtain a shaft-like protrusion.

Therefore, it is now possible to form shaft-like protrusions, which is difficult with normal drawing processing, by press forming, and the manufacturing cost of various parts with shafts such as cylindrical or prismatic shapes can be reduced. .

In addition, if the inner dimension of the recessed part formed on the back side of the plate material is made larger than the outer dimension of the axial projection, it will be easier to extrude the required amount of material in the previous process, and the extrusion height of the material will be If the height is equal to or greater than the height of the protrusion, it becomes easier to finish with high precision in a subsequent process, and it becomes even easier to form the shaft-like protrusion with a predetermined precision.

[Brief explanation of the drawing]

Fig. 1 (a) to (C) are explanatory diagrams of the processing steps of an embodiment of the present invention, Fig. 2 is a cross-sectional view of an example of a molded shaft-like protrusion, and Fig. 3 is an example of the part after processing. FIG. 1a... Extrusion punch, 1b, 1c... Molding punch, 2a, 2b, 2c... Die mold, 3... Plate material,
4. Axial protrusion, 4a, 4b. Protrusion in the middle of processing, 6. Part, 12a, 12b, l 2 c - Large diameter part (large size part)
, 42a, 42b, 42c - recessed step. Patent applicant Tachibana Seiki Co., Ltd.

Claims (3)

[Claims] (1) A pre-process of extruding the amount of material necessary to form the shaft-like protrusion from the plate using an extrusion punch with a large-sized part around the base, and a forming punch to define the extruded part from the plate. A method for processing a shaft-like protrusion by press molding, the method comprising: a post-process of forming into the shape and dimensions of. (2) The method for processing a shaft-shaped projection by press forming according to claim 1, wherein the inner dimension of the recessed step formed in the plate material by the large-sized portion of the extrusion punch is larger than the outer dimension of the shaft-shaped projection. (3) The method for processing a shaft-like protrusion by press molding according to claim 1 or 2, wherein the material is extruded to at least the height of the shaft-like protrusion in the previous step.