JP2002346653A - Progressive press-working method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a progressive press-working method which reduces manufacturing cost by removing strength decline of a processed part accompanying shearing and by getting rid of flatness decrease brought about by press-working. SOLUTION: A product is manufactured through a sequence of plural press- workings on a belt-like metal plate 16, as follows: in the first process P1, the range of the belt-like metal plate to be processed at the next process is heated before press-working is made; in the second process P2, the press-working including a work accompanied by the cutting such as a half die cutting or the like is made to the heated range of the metal plate under the condition that the elongation percentage of the heated range of the metal plate is bigger than that at ordinary temperature; and in the third process P3, the press-working including such processings to correct distortions as a flat corrective shaping or the like is made to the heated range of the metal plate under the condition that the temperature of the heated range is lower than that in the second process but the tensile strength of the heated range is smaller than that at normal temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a progressive press working method for manufacturing a product by sequentially performing a plurality of press workings on a strip-shaped metal plate.

[0002]

2. Description of the Related Art First, an example of a conventional progressive press working method according to the prior art will be described for processing a reclining gear 20 used for an automobile seat as shown in FIGS. This reclining gear 20 is provided with a support hole 23 at the center of a large half-punched portion 21 formed to be concave in the center.
A tooth 21b forming an internal gear sector gear is formed at a part of the arc-shaped edge of the sector 21a formed on one side. An arc-shaped contact surface 22 centering on the support hole 23 is formed in the fan-shaped portion 21a, and an arc projection 24 centering on the support hole 23 is formed on the opposite side. Further, two mounting holes 25 having a chamfered portion 25a and two protrusions 26 having a center hole are formed in a flat peripheral portion 20a outside the half blanking portion 21.

[0003] The reclining gear 20 has a tooth portion 2 which meshes with a member provided in a half blanking portion 21 due to its function.
The accuracy of the shape of 1b is required. In addition, the flatness of the contact surface 22 that abuts and supports the side surface of the member and the peripheral portion 20a of the reclining gear 20, and the parallelism between the peripheral portion 20a and the contact surface 22 (hereinafter, simply referred to as flatness Is required). Products that require shearing precision such as half-punching and other types of products that require the accuracy of the shearing part and the flatness of other parts are not limited to reclining gears, but include seats such as reclining guides, seat ratchets, and seat hooks. There are many parts and door parts such as door latches and door hooks.

[0004] When manufacturing such a reclining gear, the progressive press working method uses, as shown in FIG.
In the wound state, a strip-shaped metal plate 16 such as a strip-shaped steel plate supported by the uncoiler 10 is pulled out, straightened through a leveler 11, and then fed to the press device 1 by the feeder 12 for processing. Although shown in a simplified manner in FIG. 7, the press device 1 has three processing steps Q <b> 1 to Q
3 is provided. Strip-shaped steel plate 16 made of spheroidized annealed material sent to press device 1
Next, as shown in FIG. 8, the next cold working is performed in each working station. That is, in the first processing station, processing such as punching of the pilot hole, punching out of the contact surface 22, punching out of the mounting hole 25, and half punching out of the projection 26 is performed (shown by a thick solid line in the first step Q1 in FIG. 8). Then, in the next processing station, the half punching of the half punching portion 21, the punching out of the support hole 23, the half punching out of the arc projection 24, the punching out of the projection 26, the processing of the chamfered portion 25a of the mounting hole 25, etc. are performed (second). (Indicated by a thick solid line in step Q2),
At the last processing station, processing such as outline punching is performed (indicated by a thick solid line in the third step Q2). In this conventional technique, quenching and tempering are continuously performed, and the flatness is reduced. Therefore, a plurality of reclining gears 20 are tightened between the correcting jigs so that the portions requiring flatness are brought into contact with each other and corrected. The flatness is improved by performing press tempering, the flatness of both surfaces of the reclining gear 20 is further increased by belt polishing, and the surface is finished by babel processing.

[0005] In contrast to the above-mentioned example of cold working, a method of performing press working by heating is disclosed in JP-A-2000-03334.
As disclosed in JP-A-35-35, there is a press working method in which a work is heated by a high frequency heater and then pressed by a fine blanking method while holding the work in a pressing direction. However, the press working method disclosed here is only a simple fine blanking method, and there is no suggestion as to the applicability of the half blanking press working and the progressive press working method including the same.

[0006]

In the above-mentioned first prior art, since the pressing in each step is performed by cold working, a spheroidized annealing material is required as the strip-shaped steel plate 16, and the cold working is required. There is a problem that the half punched portion reaches the breaking limit and the strength is reduced. Furthermore, since the springback is large, the flatness after processing is reduced, and the residual stress accompanying the processing is large, so that the flatness after quenching and tempering is also reduced. Since planar polishing is required, there is a problem that the number of processing steps increases and the manufacturing cost increases.

The present invention solves each of these problems,
It is an object of the present invention to reduce a manufacturing cost by eliminating a decrease in strength of a processed portion accompanied by a shearing portion such as a half-blanked portion, and a reduction in planar strength due to springback or residual stress after press working.

[0008]

For this purpose, a progressive press working method according to the present invention is directed to a progressive press working method for manufacturing a product by sequentially performing a plurality of press workings on a strip-shaped metal plate. A first step of heating the range to be processed next to the metal plate to a temperature at which the elongation percentage is higher than room temperature, and a temperature at which the elongation rate of the heated range of the strip-shaped metal plate is higher than room temperature. A second step of performing a press process involving shearing in the same range in a state where the temperature is lower than that of the second step in which the heated range of the strip-shaped metal plate is lower than that of the second step; In this state, the method comprises a third step of performing press working including processing for correcting distortion within the same range.

In the invention of the preceding paragraph, it is preferable that the press working involving shearing in the second step is a half blanking processing, and the press working for correcting distortion in the third step is a flattening forming.

The heating in the first step of the invention of the preceding two aspects is preferably performed by a high-frequency heating device.

Further, it is desirable that the material heated by the high frequency heating device before being fed into the press device is fed out of the press device using a feeder.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a progressive press working method according to the present invention will be described with reference to FIGS. 1, 2, 4 and 5. FIG. FIG. 1 is a view showing the overall arrangement of the apparatus used in this embodiment. FIG. 6 shows that a heating coil 14a of a high-frequency heating apparatus 14 for heating a steel strip 16 is provided between a feeder 12 and a pressing apparatus 13. The only difference is the prior art shown. The reclining gear 20 manufactured according to this embodiment is the one shown in FIGS. 4 and 5 as described in the above-mentioned prior art. The strip-shaped steel plate 16 is a hot-rolled material of structural carbon steel (S30C),
Tensile strength σB, elongation δ, and shrinkage Ψ for that temperature
Are as shown in FIG.

The apparatus used in this embodiment includes an uncoiler 10, a leveler 11, a feeder 12, and a press device 13.
And a high-frequency heating device 14, the heating coil 1
The heating coil 14a of the high-frequency heating device 14 constituting the heating station corresponding to the first step P1 shown in FIG. 2 is provided between the feeder 12 and the pressing device 13 and the pressing device 13 shown in FIG. 2nd process P2 and 3rd
The apparatus is the same as the apparatus used in the conventional technique shown in FIG. 7, except that two processing stations corresponding to the process P3 are provided. In the progressive press working method according to this embodiment, as shown in FIG.
The belt-shaped steel plate 16 supported by the belt 0 is pulled out and the leveler 11 is pulled out.
And then the feeder 12 intermittently feeds (rolls in) the press device 13 through the heating coil 14 a of the high-frequency heating device 14. The portion provided with the heating device 14a corresponds to the first step P shown in FIG.
1 is a heating station in which the pressing device 13 is shown in a simplified manner in FIG.
Two processing stations corresponding to the process P2 and the third process P3 are provided.

In the first step P1, the high-frequency heating device 14 outputs the oscillated high-frequency current to the heating coil 14a to heat the steel strip 16 in the heating station by electromagnetic induction. As a result, the range of the strip-shaped steel plate 16 which is fed to the press device 13 and processed next is a temperature range in which breakage is prevented during the half-punching press processing of the half-punched portion 21, that is, the elongation δ is larger than normal temperature. The temperature is rapidly increased to a temperature range of 550 to 600 ° C. or more (see a temperature range A in FIG. 6).

The range of the strip-shaped steel plate 16 heated by the high-frequency heating device 14 is transferred from the inside of the heating coil 14a to the first working station in the press device 13, and has a temperature in the temperature range A shown in FIG. In the state, the second step P
2, the punching of the pilot, the half punching of the half punched portion 21, the punching out of the contact surface 22, the half punching of the arc projection 24, and the punching out of the support hole 23 and the mounting hole 25 are performed (FIG. 2). (A thick solid line is shown in the second step P2). The temperature of the heated range of the strip-shaped steel plate 16 is determined in the second step P
2, the temperature range is lower than the temperature range A but lower than the normal temperature but the springback after processing is lower than the normal temperature, that is, the tensile strength σB is lower than the normal temperature. This is the temperature range (see temperature range B in FIG. 6). The temperature of the strip-shaped steel plate 16 is adjusted by adjusting the clearance between the mold and the strip-shaped steel plate 16 in the second step P2 to change the heat transfer state.

Next, the range of the strip-shaped steel plate 16 processed in the first processing station in the press device 13 is transferred to the second processing station in the press device 13,
In the state where the temperature is in the temperature range B shown in FIG.
Processing in step P3, ie, punching of the outer shape, punching of the projection 26, processing of the chamfered portion 25a of the mounting hole 25 (shown by a thick solid line in the third step P3 in FIG. 2), and the peripheral portion 20a, half of the reclining gear 20 Cutout 21 and contact surface 22
A process is performed in which a is strongly pressed from both sides by a mold to perform flattening molding of these portions.

In this embodiment, since the hot-rolled material of the structural carbon steel is used as the belt-shaped steel plate 16, quenching and tempering are performed continuously. However, the flattening in the third step P3 is performed at the above-mentioned temperature. In the range B, the flatness is not reduced by quenching and tempering since the residual stress associated with the flattening molding is small, so that the press tempering and belt polishing steps as in the above-described prior art are unnecessary. Finally, the surface is finished by barrel processing, and processing of the reclining gear 20 by the progressive press working method is completed.

According to the above-described embodiment, the first step P
The range of the strip-shaped steel sheet 16 which is high-frequency-heated in 1 is a temperature range A where breakage is prevented during the half-punching press working of the half-punched portion 21 in the second step P2, that is, the elongation δ is larger than room temperature. Since the press working including the half-punching with shearing is performed in a certain temperature range, the tooth portion 21b requiring accuracy is formed only by shearing without breaking, and the joint portion of the half-punching section is broken. Does not occur and the strength does not decrease. In the third step P3, a temperature range B in which the temperature of the strip-shaped steel plate 16 is lower than the temperature range A but the springback after processing is lower than normal temperature, that is, a temperature range in which the tensile strength σB is lower than normal temperature. In B, since the press work including the flattening molding is performed, the flatness decrease due to the quenching and tempering after the press work is reduced, and the post-process for improving the flatness is not required, so that the manufacturing cost is reduced. Can be done.

In this embodiment, the heating in the first step P1 is performed by the high-frequency heating device 14, which shortens the time required to heat the strip-shaped steel plate 16. The cycle can be increased to improve the productivity.

In the above-described embodiment, S30C is used as the strip-shaped steel plate 16 or S45C
Are often used, and in these cases, quenching and tempering after progressive press working are required as described above. However, when a high-strength material such as high-carbon steel (for example, S65C) is used, quenching and tempering after progressive press working are not required, so that productivity and flatness can be further improved.

FIG. 3 shows a modification of the apparatus shown in FIG.
In the apparatus shown in FIG. 3, a feeder 15 is provided at the rear of the press device 13, and the feeder 15 sandwiches the strip-shaped steel plate 16 between a pair of rollers intermittently rotating in opposite directions. It is designed to be fed out from the press device 13. The reason why the feeder 15 having such an operation is arranged behind the press device 13 is as follows. In the apparatus of FIG. 1, the strip-shaped steel plate 16 is intermittently fed into the press device 13 from the feeder 12 located in front of the press device 13 and is intermittently transferred in the press device 13. However, the intermittent transfer and the transfer are performed in synchronization. When the strip-shaped steel plate 16 is fed into the press device 13, the strength of the strip-shaped steel plate 16 is weakened immediately after being heated by the high frequency.
Steel sheet 1 in press machine 13
When the transfer speed of the belt 6 is deviated, there is a fear that the resultant reaction force causes the belt-shaped steel plate 16 to buckle or deform and become unusable. For this reason, it is necessary to constantly check the transfer mechanism in the press device 13 and to wipe off factors that disturb the transfer speed, such as dust, so that such a shift does not occur. However, the feeder 15 is
If the belt-like steel plate 16 is set up behind and is fed out from the press device 13, the belt-like steel plate 16 can be transferred at a stable speed without constantly wiping dust. In this case, the feeder 12 on the front side is
The feeding operation is stopped at the stage when is fed into the feeder 15 on the rear side (specifically, the interval between the pair of rollers is widened, and the strip-shaped steel plate 16 only passes through the feeder 12).
The strip-shaped steel sheet 16 fed from the feeder 15 is cut into a predetermined length by a cutter 17 provided as an option, for example, and is supplied to a scrap processing step.

Although the embodiment of the present invention has been described above, the present invention is not intended to be limited to the above-described embodiment, and any progressive press working method in a form according to the gist of the present invention can be used. Such a thing may be used.

[0023]

According to the present invention, in the second step, in the state where the elongation percentage in the heated range of the strip-shaped metal plate is higher than the normal temperature, the same range is applied in the same range, for example, as in the case of the half punching. Since the press working including the processing involving the shearing is performed, the possibility that the processed part involving the shearing is broken to lower the strength is greatly reduced. Further, in the third step, in a state where the tensile strength of the heated range of the strip-shaped metal plate is at a temperature lower than room temperature, a press including a process of correcting distortion such as flattening forming is performed in the same range. Since the processing is performed, the flatness does not decrease due to the springback or the residual stress after the press processing, and the post-processing for improving the flatness is not required, so that the manufacturing cost can be reduced.

According to the first step, in which the heating in the first step is performed by the high-frequency heating device, the time required to heat the working range of the strip-shaped steel sheet is shortened, so that the working cycle of the progressive press working method is increased. Thus, productivity can be improved.

Further, since the strip-shaped steel sheet is fed out by a feeder installed on the rear side of the press, the transfer of the strip-shaped steel sheet in the press can be performed at a stable speed.
There is no buckling of the strip-shaped steel sheet which has been weakened by the high-frequency heating.

[Brief description of the drawings]

FIG. 1 is a view showing an overall arrangement of an apparatus used in an embodiment of a progressive press working method according to the present invention.

FIG. 2 is a view showing each processing step in the embodiment shown in FIG. 1;

FIG. 3 is a diagram showing a modification of the overall arrangement of the apparatus shown in FIG.

FIG. 4 is a plan view showing a shape of an example of a product manufactured in the embodiment shown in FIG. 1;

FIG. 5 is a sectional view taken along line 5-5 in FIG. 4;

FIG. 6 is a diagram showing characteristics of tensile strength, elongation and shrinkage with respect to temperature of an example of a material used for a strip-shaped metal plate used in the embodiment shown in FIG.

FIG. 7 is a view showing the overall arrangement of an apparatus used in an example of a progressive press working method according to the related art.

8 is a diagram showing each processing step in the embodiment shown in FIG.

[Explanation of symbols]

13 ... press device, 15 ... rear side feeder, 1
6 ... Strip metal plate (Strip steel plate), 20 ... Product (reclining gear), P1 ... First step, P2 ...
2nd process, P3 ... 3rd process

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4E003 AA02 CA03 4E048 EA04

Claims (4)

[Claims] 1. A progressive press working method for manufacturing a product by sequentially performing a plurality of press workings on a strip-shaped metal plate, wherein an elongation percentage in a range to be processed next to the strip-shaped metal plate before the pressing is greater than room temperature. A first step of heating above the temperature,
A second step of performing a pressing process involving shearing in the same range in a state where the elongation percentage of the heated range of the strip-shaped metal plate is higher than room temperature; and A third step of performing a press working including a processing to correct the strain in the same range in a state where the range is lower than the second step but the tensile strength is lower than the normal temperature. And progressive press working method. 2. The progressive press working method according to claim 1, wherein the press working involving shearing in said second step is half blanking, and said press working for correcting distortion in said third step is plane forced forming. A progressive press working method characterized by the above-mentioned. 3. The progressive feeding method according to claim 1, wherein the heating in the first step is performed by a high-frequency heating device. 4. A progressive press working method for manufacturing a product by sequentially performing a plurality of press workings on a band-shaped metal plate, wherein the band-shaped metal plate is heated by a high-frequency heating device provided in front of a press device for performing the press working. A press working method, wherein the strip-shaped metal plate is fed from the press device by a feeder provided behind the press device.