JP2006334660A - Press forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a press forming method capable of improving productivity while securing surface quality of a press formed product. <P>SOLUTION: The press forming method is to form a workpiece into a designated shape employing a press forming apparatus 1, which comprises a fixed die 3, a movable die 5, and restraining member 6 to restrain the periphery of workpiece 20 cooperating with the movable die. The method comprises an approaching step 100 to move the movable die in an approaching direction to the fixed die, a touching step 200 to restrain the periphery of the workpiece with the movable die and the restraining member by making the movable die touched to the workpiece, a forming step 300 to move the movable die in the approaching direction to the fixed die up to the position where the workpiece is formed into the designated shape, and a die releasing step 400 to move the movable die in the departing direction from the fixed die. In the touching step, the moving speed of the movable die is not more than 700 mm/sec, while in the forming step, the moving speed of the movable die is not less than 700 mm/sec. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a press molding technique. More specifically, the present invention relates to a technique for improving productivity while maintaining the surface quality of a workpiece to be press-molded.

  2. Description of the Related Art Conventionally, a press forming method using a press forming apparatus including a movable mold, a fixed mold, and a movable mold or a restraining member that restrains a peripheral portion of a workpiece between the fixed mold and the movable mold is known. .

In press molding (especially draw molding) using a conventional press molding apparatus, the movable mold approaches the fixed mold, contacts the workpiece, and reaches the position where the workpiece is molded into a predetermined shape. The moving speed and the moving speed of the movable mold when the movable mold is separated from the fixed mold in order to take out the press-molded product from the press molding apparatus were substantially the same.
Therefore, in order to improve the productivity of conventional press molding, it is necessary to shorten the press molding cycle (time required for one press molding) by increasing the moving speed.

  However, when the moving speed of the movable mold is increased, the surface quality is deteriorated such that wrinkles, surface distortion, etc. occur on the surface of the press-formed product. In particular, when the surface quality of a press-molded product such as a panel part for an automobile is regarded as important, the deterioration of the surface quality accompanying an increase in the moving speed of the movable mold becomes a big problem.

In order to eliminate such problems, only the process in which the moving speed of the movable mold is considered to have no effect on the surface quality of the press-molded product in the press molding cycle, that is, the process in which the movable mold approaches the workpiece is accelerated. Therefore, a movable motion control method that shortens the press molding cycle has been studied. For example, it is as described in Patent Document 1 to Patent Document 3.
Japanese Patent Laid-Open No. 10-277797 Japanese Patent Laid-Open No. 10-277798 JP 2001-198632 A

However, in the motion control method described in Patent Document 1 to Patent Document 3, the moving speed of the movable mold in the phase in which the movable mold is molding the workpiece is increased while ensuring the surface quality of the press-formed product. It was difficult to improve productivity.
In view of the circumstances as described above, the present invention provides a press molding method capable of improving productivity while ensuring the surface quality of a press molded product.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

That is, in claim 1,
Fixed type,
A movable mold that moves between a position where the workpiece is formed in a predetermined shape by approaching the stationary mold and a position where the workpiece can be taken out from the fixed mold;
A restraining member that is provided on the fixed mold and restrains the peripheral edge of the workpiece with the movable mold;
A press molding method for molding the workpiece into a predetermined shape using a press molding apparatus comprising:
An approach step of moving the movable mold in a direction approaching the fixed mold;
A contact step of bringing the movable mold into contact with the work and restraining a peripheral edge of the work with the movable mold and the restraining member;
A molding step of moving the movable mold in a direction approaching the fixed mold to a position for molding the workpiece into a predetermined shape;
A mold release step of moving the movable mold in a direction away from the fixed mold;
Comprising
While the moving speed of the movable mold in the contact step is 700 mm / sec or less,
The moving speed of the movable mold in the molding step is set to 700 mm / sec or more.

In claim 2,
The moving type moving speed in the approaching step is set to 700 mm / sec or more.

In claim 3,
The moving speed of the movable mold in the mold release step is set to 700 mm / sec or more.

In claim 4,
A bead is formed on the restraining member or the movable mold.

In claim 5,
Fixed type,
A movable mold that moves between a position where the workpiece is formed in a predetermined shape by approaching the stationary mold and a position where the workpiece can be taken out from the fixed mold;
A restraining member provided on the movable die and restraining the peripheral edge of the workpiece with the fixed die;
A press molding method for molding the workpiece into a predetermined shape using a press molding apparatus comprising:
An approach step of moving the movable mold in a direction approaching the fixed mold;
A contact step of bringing the restraining member into contact with the workpiece and restraining a peripheral edge of the workpiece with the restraining member and the fixed mold;
A molding step of moving the movable mold in a direction approaching the fixed mold to a position for molding the workpiece into a predetermined shape;
A mold release step of moving the movable mold in a direction away from the fixed mold;
Comprising
While the moving speed of the movable mold in the contact step is 700 mm / sec or less,
The moving speed of the movable mold in the molding step is set to 700 mm / sec or more.

In claim 6,
The moving type moving speed in the approaching step is set to 700 mm / sec or more.

In claim 7,
The moving speed of the movable mold in the mold release step is set to 700 mm / sec or more.

In claim 8,
A bead is formed on the restraining member or the fixed mold.

  As effects of the present invention, the following effects can be obtained.

  In claim 1, it is possible to improve the productivity of press molding while ensuring the surface quality of the press molded product.

  According to the second aspect, it is possible to further improve the productivity of press molding while ensuring the surface quality of the press molded product.

  According to the third aspect, it is possible to further improve the productivity of press molding while ensuring the surface quality of the press molded product.

  According to the fourth aspect of the present invention, it is possible to reliably restrain the peripheral portion of the workpiece with the movable die and the restraining member.

  According to the fifth aspect, it is possible to improve the productivity of press molding while ensuring the surface quality of the press molded product.

  In claim 6, it is possible to further improve the productivity of press molding while ensuring the surface quality of the press molded product.

  According to the seventh aspect, it is possible to further improve the productivity of press molding while ensuring the surface quality of the press molded product.

  According to the eighth aspect of the present invention, it is possible to reliably restrain the peripheral portion of the workpiece with the restraining member and the fixed mold.

Below, the structure of the press molding apparatus 1 which is a 1st Example of the press molding apparatus based on this invention is demonstrated using FIG.
The press forming apparatus 1 forms a workpiece 20 into a predetermined shape (particularly draw forming).
Here, the “workpiece” in the present application is an object that is formed into a predetermined shape by a press forming apparatus, and is usually a plate-like member made of a steel material or other metal material.

  The press molding apparatus 1 includes a bolster 2, a lower mold 3, a slide ram 4, an upper mold 5, a cushion ring 6, guide pins 7 and 7, coil springs 8 and 8 and the like.

  The bolster 2 is a structure that forms the lower part of the press molding apparatus 1 and is fixed to the ground or the like.

The lower mold 3 is an embodiment of a fixed mold according to the present invention, and is provided on the upper surface of the bolster 2.
Here, the “fixed mold” in the present application refers to a member that is fixed at a predetermined position at the time of press molding among members constituting a mold included in the press molding apparatus.

A projection 3a is formed along the shape of the press-molded product at a substantially central portion of the upper surface of the lower mold 3 of this embodiment.
Here, the “press-formed product” in the present application refers to a work formed into a predetermined shape by a press-forming device.
The press-formed product of this example is a panel for an automobile, and high surface quality is required.

The slide ram 4 is a member that is disposed above the bolster 2 and moves in a direction approaching the bolster 2 and a direction away from the bolster 2, that is, a vertical direction.
The slide ram 4 of this embodiment is moved in the vertical direction by an AC servo motor (not shown). The AC servo motor can appropriately adjust the moving speed of the slide ram 4 within a predetermined range.

The upper mold 5 is an embodiment of a movable mold according to the present invention.
Here, the “movable mold” in the present application refers to a position in which a workpiece is formed in a predetermined shape by approaching the fixed mold, and apart from the fixed mold among members constituting the mold included in the press molding apparatus. It refers to the one that moves between positions where the workpiece can be taken out.
In the press molding apparatus 1 of the present embodiment, the upper die 5 which is a movable die is disposed above and the lower die 3 which is a stationary die is disposed below. “Dead point” refers to the position of the upper mold 5 when the workpiece 20 is separated from the lower mold 3 to a position where the workpiece 20 can be taken out of the press molding apparatus 1.
In the present embodiment, the position when the upper mold 5 is moved to the lowest position, that is, the “bottom dead center” is the distance between the upper mold 5 and the lower mold 3 when the upper mold 5 approaches the lower mold 3. It refers to a position where the workpiece 20 is molded into a predetermined shape by plastically deforming the workpiece 20.
The upper mold 5 of this embodiment has a distance between the top dead center and the bottom dead center, that is, a stroke of about 1000 mm.

The upper mold 5 is fixed to the lower surface of the slide ram 4. In a substantially central portion of the lower surface of the upper mold 5 of this embodiment, a recess 5a is formed along the shape of the press-formed product.
A bead 5 b is formed on the peripheral edge of the lower surface of the upper mold 5. The bead 5b is a protrusion formed in a ring shape so as to surround the recess 5a.

The cushion ring 6 is an embodiment of the restraining member according to the present invention.
Here, the “restraint member” in the present embodiment is a movable type that restrains the peripheral portion of the workpiece.
The cushion ring 6 is a ring-shaped member having a hole through which the projection 3a of the lower mold 3 can pass substantially in the center, and is provided on the lower mold 3 via guide pins 7 and 7 and coil springs 8 and 8 which will be described later. Thus, it can slide in the vertical direction with respect to the lower mold 3.
The cushion ring 6 restrains the periphery of the workpiece 20 by gripping the periphery of the workpiece 20 with the upper mold 5.
A bead groove 6 a is formed on the upper surface of the cushion ring 6, and portions other than the bead groove 6 a on the upper surface of the cushion ring 6 are smooth.
The bead groove 6 a is a groove formed in a ring shape so as to surround the hole of the cushion ring 6, and the shape corresponds to the bead 5 b formed on the peripheral edge of the lower surface of the upper mold 5.

  The guide pins 7 and 7 are substantially cylindrical members provided on the lower surface of the cushion ring 6. The guide pins 7 and 7 are inserted through sliding holes 3b and 3b formed at the peripheral edge of the lower mold 3 so as to be slidable in the vertical direction.

The coil springs 8 and 8 are attached to the guide pins 7 and 7, respectively. One ends of the coil springs 8 and 8 are in contact with the peripheral edge of the upper surface of the lower mold 3, and the other end is in contact with the lower surface of the cushion ring 6.
The coil springs 8 and 8 urge the cushion ring 6 upward. As shown in FIG. 1, when the work 20 is placed on the upper surface of the cushion ring 6 and no other external force is applied to the cushion ring 6, the upper surface of the cushion ring 6 is the upper end of the protrusion 3 a of the lower mold 3. It arrange | positions in the position which becomes flush | level, or a position higher than the upper end part of the processus | protrusion 3a.

Below, the 1st Example of the press molding method which concerns on this invention is described using FIG. 1 thru | or FIG.
The first embodiment of the press forming method according to the present invention is a method of forming the workpiece 20 into a predetermined shape using the press forming apparatus 1.
As shown in FIGS. 2 and 3, the first embodiment of the press molding method according to the present invention includes an approach process 100, a contact process 200, a molding process 300, a mold release process 400, and the like.

The approach process 100 is a process in which the upper mold 5 moves in a direction approaching the lower mold 3.
As shown in FIG. 1, at the start of the approaching process 100, the upper mold 5 is located at the top dead center, and the workpiece 20 is placed on the upper surface of the cushion ring 6.

Next, the upper mold 5 moves in a direction approaching the lower mold 3. At this time, the moving speed (approaching speed) of the upper mold 5 is 20 SPM (Stroke Per Minute) as shown in FIG.
Here, “SPM” in the present application represents the number of reciprocations per minute when the movable mold reciprocates between the top dead center and the bottom dead center of the press molding apparatus. This is one of the units representing the moving speed, and thus the productivity of the press forming apparatus.
When the upper mold 5 reaches a position just above the workpiece 20 placed on the cushion ring 6, that is, a position as close as possible to the workpiece 20 within a range not contacting the workpiece 20 (for example, a position several tens of mm from the upper surface of the workpiece 20). Thus, the approaching process 100 ends.

  When the approach process 100 is completed, the process proceeds to the contact process 200.

The contact process 200 is a process in which the lower surface of the upper die 5 is brought into contact with the workpiece 20 and the peripheral portion of the workpiece 20 is restrained by the upper die 5 and the cushion ring 6.
As shown in FIG. 3, in the contact process 200, the moving speed (contact speed) of the upper mold 5 is reduced from 20 SPM, which is the moving speed in the approaching process 100, to 14 SPM, and then held at 14 SPM.
In the case of the present embodiment, when the unit of the moving speed of the upper mold 5 is converted from SPM to mm / sec, 14 SPM is about 700 mm / sec.
As a result, as shown in FIG. 4, a portion corresponding to the bead 5 b formed on the lower surface of the upper mold 5 and the bead groove 6 a formed on the upper surface of the cushion ring 6 in the peripheral portion of the workpiece 20 precedes the other portions. Then, plastic deformation occurs along the shape of the bead 5b and the bead groove 6a, and the peripheral portion of the workpiece 20 is constrained by the upper mold 5 and the cushion ring 6.
Here, “restraining the workpiece” in the present application refers to preventing the workpiece from shifting with respect to the restraining member by gripping the peripheral edge of the workpiece with the upper die or the lower die and the restraining member. Shall.
The contact process 200 ends when the peripheral edge of the workpiece 20 is restrained by the upper mold 5 and the cushion ring 6.

  When the contact process 200 is completed, the process proceeds to the molding process 300.

The forming step 300 is a step of moving the upper die 5 in a direction approaching the lower die 3 to a position where the workpiece 20 is formed into a predetermined shape.
As shown in FIG. 3, in the molding process 300, the moving speed (molding speed) of the upper mold 5 is accelerated from 14 SPM, which is the moving speed in the contact process 200, to 20 SPM, and then held at 20 SPM.
In the molding step 300, since the upper mold 5 moves downward, the substantially central portion of the work 20 comes into contact with the recess 5a of the upper mold 5 and the protrusion 3a of the lower mold 3, and plastically deforms along these shapes. During this time, the cushion ring 6 is urged upward by the coil springs 8 and 8, so that the cushion ring 6 is integrated with the upper die 5 while maintaining the state where the peripheral edge of the workpiece 20 is restrained by the upper die 5. Move down to.
Then, as shown in FIG. 5, the upper die 5 stops when reaching the bottom dead center, and the molding process 300 ends.

  When the molding process 300 is completed, the process proceeds to the mold release process 400.

The mold release process 400 is a process of moving the upper mold 5 in a direction away from the lower mold 3.
As shown in FIG. 3, in the mold release step 400, the moving speed (mold release speed) of the upper mold 5 is maintained at 20 SPM.
As shown in FIG. 6, when the upper mold 5 reaches the top dead center, the mold release process 400 ends.
After the mold release step 400 is completed, the workpiece 20 formed into a predetermined shape, that is, a press-formed product is taken out of the press-forming apparatus 1.

  Below, the relationship between the moving speed of each process which comprises the press molding method which concerns on this invention, and the surface quality of a press molded product is demonstrated using FIGS. 7-10.

FIG. 7 shows the surface quality of a press-formed product obtained by a conventional press-forming method and the surface quality of a press-formed product obtained by the first embodiment of the press-forming method according to the present invention (hereinafter referred to as “panel quality” as appropriate). It is a figure which shows the determination result of notation.
Here, the “conventional press molding method” in FIG. 7 is such that the moving speeds of the steps of the approaching process, the contacting process, the molding process, and the mold releasing process are all the same.
Note that the surface quality (panel quality) of the press-formed product shown in FIG. 7 is determined by visual inspection or palpation by the operator, but can also be determined using a commercially available surface shape measuring instrument or the like.

No. of FIG. 10 to No. As shown in FIG. 16, the panel quality in the conventional press molding method is good (◯) when the moving speed of the movable mold is 14 SPM or less, but poor (×) when the moving speed of the movable mold is faster than 14 SPM. It becomes.
Here, the surface distortion and wrinkles that cause the panel quality to deteriorate are because the work is not sufficiently restrained in the contact process. It is known to occur by flowing into the section.

Therefore, when examining the relationship between the work restraint state in the contact process and the panel quality, as shown in FIG. 8, the pressing force N (horizontal axis) of the cushion ring 6 against the upper mold 5 and the work 20 side When the relationship between the force P (vertical axis) required for pulling out in the direction (perpendicular to the moving direction of the upper mold 5) is that there is no gap between the work 20 and the upper mold 5 (black circle), the work 20 and the upper It was clarified that different linear relations were exhibited when there was a gap between the mold 5 (white circles).
Further, when there is a gap between the workpiece 20 and the upper mold 5, the pulling force P decreases rapidly as the gap increases, that is, the peripheral edge of the workpiece 20 is moved between the upper mold 5 and the cushion ring 6. It became clear that the restraining force decreased.
Here, the “gap between the workpiece 20 and the upper die 5” is represented by ΔT shown in FIG.

  Then, when the relationship between the moving speed of the movable mold in the contact process and the amount of lifting from the movable workpiece, that is, the gap between the workpiece 20 and the upper mold 5 is examined, as shown in FIG. It has been clarified that the amount of lift rises sharply when the moving speed of the mold 5 exceeds 14 SPM.

From the above results, in the conventional press molding method, when the moving speed of the movable mold exceeds 14 SPM, the surface quality of the press-molded product is deteriorated, but the main factor is “moving speed of the movable mold in the contact process”. Presumed to be.
The reason why the gap between the workpiece 20 and the upper mold 5 is generated when the moving speed of the movable mold is increased in the contact process is that the upper mold 5 is placed on the cushion ring 6 when the moving speed of the upper mold 5 is increased. Since the kinetic energy given to the cushion ring 6 and the workpiece 20 when contacting the workpiece 20 is also large, the cushion ring 6 may bounce against the upper die 5 against the urging force of the coil springs 8 and 8. It is done.

Based on the above results, the results of carrying out the press molding method according to the present invention using the press molding apparatus 1 are shown in No. 1 of FIG. 4 to No. 9 shows. In FIG. In No. 9, the movable moving speed in the contact step is zero, but more strictly, it indicates “a value close to zero”.
No. of FIG. 4 to No. As shown in FIG. 9, the moving speed of the movable mold in the approach process, the molding process, and the mold releasing process is maintained at 20 SPM, where the surface quality of the press-molded product is poor in the conventional press molding method. The surface quality of the press-formed product was good under the condition that the moving speed of the movable mold in the contact process was 14 SPM or less.
In addition, in FIG. 1 to No. As shown in FIG. 3, when the moving speed of the movable mold in the approach process, the molding process, and the mold releasing process is all maintained at 20 SPM, and the contact process speed is maintained at a speed greater than 14 SPM, the surface quality of the press-molded product Became defective.
Accordingly, it is confirmed that the moving speed of the movable mold in the contact process is the main factor determining the surface quality of the press-formed product, and the moving speed (contact speed) of the movable mold in the contacting process is 14 SPM or less (700 mm / sec or less). Then, it became clear that the surface quality of the press-formed product can be maintained even if the moving speed (molding speed) of the movable mold in the molding process is 14 SPM or more (700 mm / sec or more).

As described above, the first embodiment of the press molding method according to the present invention is as follows.
Lower mold 3 and
An upper die 5 that moves between a position where the workpiece 20 is formed in a predetermined shape by approaching the lower die 3 and a position where the workpiece 20 can be taken out from the lower die 3;
A cushion ring 6 provided on the lower mold 3 and restraining the peripheral edge of the workpiece 20 with the upper mold 5;
A press molding method for molding a workpiece 20 into a predetermined shape using a press molding apparatus 1 comprising:
An approaching step 100 for moving the upper die 5 in a direction approaching the lower die 3;
A contact step 200 in which the upper die 5 is brought into contact with the workpiece 20 and the peripheral portion of the workpiece 20 is restrained by the upper die 5 and the cushion ring 6;
A molding step 300 for moving the upper mold 5 in a direction approaching the lower mold 3 to a position where the workpiece 20 is molded into a predetermined shape;
A mold release step 400 for moving the upper mold 5 away from the lower mold 3;
Comprising
While the moving speed of the upper mold 5 in the contact process 200 is 700 mm / sec or less,
The moving speed of the upper mold 5 in the molding process 300 is set to 700 mm / sec or more.

By comprising in this way, it is possible to enlarge the average value of the moving speed of the upper mold | type 5 rather than the conventional press molding method, ensuring the surface quality of a press molded product.
As a result, it is possible to reduce the cycle time of press molding while ensuring the surface quality of the press-molded product, that is, to improve productivity.

The first embodiment of the press molding method according to the present invention is as follows:
The moving speed of the upper mold 5 in the approaching process 100 is set to 700 mm / sec or more.

By comprising in this way, it is possible to make the average value of the moving speed of the upper mold | type 5 larger further than the conventional press molding method, ensuring the surface quality of a press molded product.
As a result, it is possible to further shorten the press molding cycle time while ensuring the surface quality of the press molded product, that is, to further improve the productivity.

The first embodiment of the press molding method according to the present invention is as follows:
The moving speed of the upper mold 5 in the mold release process 400 is 700 mm / sec or more.

By comprising in this way, it is possible to make the average value of the moving speed of the upper mold | type 5 larger further than the conventional press molding method, ensuring the surface quality of a press molded product.
As a result, it is possible to further shorten the press molding cycle time while ensuring the surface quality of the press molded product, that is, to further improve the productivity.

The first embodiment of the press molding method according to the present invention is as follows:
A bead 5 b is formed on the upper mold 5.
By configuring in this way, it is possible to reliably restrain the peripheral edge of the workpiece 20 with the upper mold 5 and the cushion ring 6.

In addition, although the press molding apparatus 1 of a present Example is a single shot type press molding apparatus, this invention is applicable also to a transfer type press molding apparatus.
Further, the material of the lower mold 3, the upper mold 5 and the cushion ring 6 of the press molding apparatus 1 of the present embodiment is made of a steel material used for a normal mold, but the present invention is a material having a low coefficient of restitution or Young's modulus ( For example, the present invention can be applied to the case where most metal materials except for a zinc alloy or the like are used as materials for the lower mold 3, the upper mold 5 and the cushion ring 6.

  Below, the structure of the press molding apparatus 101 which is a 2nd Example of the press molding apparatus based on this invention is demonstrated using FIG.

  The press molding apparatus 101 includes a bolster 102, a lower mold 103, a slide ram 104, an upper mold 105, a cushion ring 106, guide pins 107 and 107, coil springs 108 and 108, and the like.

  The bolster 102 is a structure that forms the lower part of the press molding apparatus 101, and is fixed to the ground or the like.

The lower mold 103 is an embodiment of a fixed mold according to the present invention, and is provided on the upper surface of the bolster 102.
A recess 103 a is formed along the shape of the press-molded product at a substantially central portion of the upper surface of the lower mold 103 of this embodiment.
In addition, a bead groove 103 b is formed on the peripheral edge of the upper surface of the lower mold 103. The bead groove 103b is a groove formed in a ring shape so as to surround the depression 103a.

The slide ram 104 is a member that is arranged above the bolster 102 and moves in a direction approaching the bolster 102 and a direction away from the bolster 102, that is, a vertical direction.
The slide ram 104 of this embodiment is moved in the vertical direction by an AC servo motor (not shown). The AC servo motor can appropriately adjust the moving speed of the slide ram 104 within a predetermined range.

The upper mold 105 is an embodiment of a movable mold according to the present invention.
The upper mold 105 of this embodiment has a distance between the top dead center and the bottom dead center, that is, a stroke of about 1000 mm.

  The upper mold 105 is fixed to the lower surface of the slide ram 104. A projection 105a is formed along the shape of the press-formed product at a substantially central portion of the lower surface of the upper mold 105.

The cushion ring 106 is an embodiment of a restraining member according to the present invention.
Here, the “restraint member” in the present embodiment restrains the peripheral portion of the work with a fixed die.
The cushion ring 106 is a ring-shaped member having a hole through which the projection 105a of the upper mold 105 can pass substantially in the center, and is provided on the upper mold 105 via guide pins 107 and 107 and coil springs 108 and 108, which will be described later. Thus, the upper mold 105 can be slid in the vertical direction.
The cushion ring 106 holds the peripheral edge of the workpiece 20 with the lower mold 103 to restrain the peripheral edge of the workpiece 20.
A bead 106 a is formed on the lower surface of the cushion ring 106, and portions other than the bead 106 a on the lower surface of the cushion ring 106 are smooth.
The bead 106 a is a protrusion formed in a ring shape so as to surround the hole of the cushion ring 106, and the shape thereof corresponds to the bead groove 103 b formed in the peripheral edge portion of the upper surface of the lower mold 103.

  The guide pins 107 and 107 are substantially cylindrical members provided on the upper surface of the cushion ring 106. The guide pins 107 and 107 are inserted through sliding holes 105b and 105b formed in the peripheral edge of the upper mold 105 so as to be slidable in the vertical direction.

The coil springs 108 and 108 are attached to the guide pins 107 and 107, respectively. One end of each of the coil springs 108 and 108 is in contact with the peripheral edge of the lower surface of the upper mold 105, and the other end is in contact with the upper surface of the cushion ring 106.
The coil springs 108 and 108 urge the cushion ring 106 downward. As shown in FIG. 11, when no external force is applied to the cushion ring 106, the lower surface of the cushion ring 106 is flush with the lower end of the protrusion 105a of the upper mold 105 or lower than the lower end of the protrusion 105a. Placed in.

Below, the 2nd Example of the press molding method which concerns on this invention is described using FIG.
The second embodiment of the press forming method according to the present invention is a method of forming the workpiece 20 into a predetermined shape using the press forming apparatus 101.
As shown in FIG. 12, the second embodiment of the press molding method according to the present invention includes an approaching step 110, a contacting step 210, a forming step 310, a mold releasing step 410, and the like.
Note that the approaching step 110, the forming step 310, and the releasing step 410 are substantially the same as the approaching step 100, the forming step 300, and the releasing step 400 shown in FIG.

The contact step 210 is a step in which the lower surface of the cushion ring 6 is brought into contact with the workpiece 20 and the peripheral portion of the workpiece 20 is restrained by the cushion ring 6 and the lower mold 103.
In the contact step 210, the moving speed (contact speed) of the upper mold 105 is decelerated from 20 SPM, which is the moving speed in the approaching step 110, to 14 SPM, and then held at 14 SPM.
In the case of the present embodiment, when the unit of the moving speed of the upper mold 105 is converted from SPM to mm / sec, 14 SPM is about 700 mm / sec.
As a result, portions of the peripheral edge portion of the work 20 corresponding to the beads 106a formed on the lower surface of the cushion ring 106 and the bead grooves 103b formed on the upper surface of the lower mold 103 follow the shapes of the beads 106a and the bead grooves 103b. Thus, the peripheral edge of the workpiece 20 is restrained by the cushion ring 6 and the lower mold 103.
The contact process 210 ends when the peripheral edge of the workpiece 20 is restrained by the cushion ring 106 and the lower mold 103.

  When the contact process 210 is completed, the process proceeds to the molding process 310.

As described above, the second embodiment of the press molding method according to the present invention is as follows.
Lower mold 103,
An upper mold 105 which moves between a position where the workpiece 20 is formed in a predetermined shape by approaching the lower mold 103 and a position where the workpiece 20 can be taken out from the lower mold 103;
A cushion ring 106 provided on the upper mold 105 and restraining the peripheral edge of the workpiece 20 with the lower mold 103;
A press molding method for molding the workpiece 20 into a predetermined shape using a press molding apparatus 101 comprising:
An approaching step 110 for moving the upper die 105 in a direction approaching the lower die 103;
A contact step 210 in which the cushion ring 106 is brought into contact with the workpiece 20, and the peripheral portion of the workpiece 20 is restrained by the cushion ring 106 and the lower mold 103;
A molding step 310 for moving the upper mold 105 in a direction approaching the lower mold 103 to a position for molding the workpiece 20 into a predetermined shape;
A mold release step 410 for moving the upper mold 105 away from the lower mold 103;
Comprising
While the moving speed of the upper mold 105 in the contact step 210 is 700 mm / sec or less,
The moving speed of the upper mold 105 in the molding step 310 is set to 700 mm / sec or more.

By configuring in this way, it is possible to increase the average value of the moving speed of the upper mold 105 as compared with the conventional press molding method while ensuring the surface quality of the press molded product.
As a result, it is possible to reduce the cycle time of press molding while ensuring the surface quality of the press-molded product, that is, to improve productivity.

Further, the second embodiment of the press molding method according to the present invention is:
The moving speed of the upper mold | type 105 in the approach process 110 shall be 700 mm / sec or more.

By configuring in this way, it is possible to further increase the average value of the moving speed of the upper die 105 as compared with the conventional press molding method while ensuring the surface quality of the press molded product.
As a result, it is possible to further shorten the press molding cycle time while ensuring the surface quality of the press molded product, that is, to further improve the productivity.

Further, the second embodiment of the press molding method according to the present invention is:
The moving speed of the upper mold 105 in the mold release process 410 is set to 700 mm / sec or more.

By configuring in this way, it is possible to further increase the average value of the moving speed of the upper die 105 as compared with the conventional press molding method while ensuring the surface quality of the press molded product.
As a result, it is possible to further shorten the press molding cycle time while ensuring the surface quality of the press molded product, that is, to further improve the productivity.

Further, the second embodiment of the press molding method according to the present invention is:
A bead 106 a is formed on the cushion ring 106.
With this configuration, it is possible to reliably restrain the peripheral edge of the workpiece 20 between the cushion ring 6 and the lower mold 103.

Sectional drawing which shows the 1st Example of the press molding apparatus of this invention in an approach process. The flowchart which shows the 1st Example of the press molding method of this invention. The figure which shows the moving speed of the movable mold | type in the 1st Example of the press molding method of this invention. Sectional drawing which shows the 1st Example of the press molding apparatus of this invention in a contact process. Sectional drawing which shows the 1st Example of the press molding apparatus of this invention in a formation process. Sectional drawing which shows the 1st Example of the press molding apparatus of this invention in a separation | spacing process. The figure which shows the relationship between the moving speed of a movable mold | type, and the surface quality of a press molded product. The figure which shows the relationship between the pressing force of a restraint member, and the extraction force of a workpiece | work. The principal part sectional drawing which shows a bead part. The figure which shows the relationship between the moving speed of the movable type | mold in a contact process, and the amount of lifting from a workpiece | work. Sectional drawing which shows the 2nd Example of the press molding apparatus of this invention in an approach process. The flowchart which shows the 2nd Example of the press molding method of this invention.

Explanation of symbols

1 Press molding equipment 3 Lower mold (fixed mold)
5 Upper mold (movable)
6 Cushion ring (restraint member)
20 Work 100 Approaching process 200 Contacting process 300 Molding process 400 Separating process

Claims (8)

Fixed type,
A movable mold that moves between a position where the workpiece is formed in a predetermined shape by approaching the stationary mold and a position where the workpiece can be taken out from the fixed mold;
A restraining member that is provided on the fixed mold and restrains the peripheral edge of the workpiece with the movable mold;
A press molding method for molding the workpiece into a predetermined shape using a press molding apparatus comprising:
An approach step of moving the movable mold in a direction approaching the fixed mold;
A contact step of bringing the movable mold into contact with the workpiece and restraining a peripheral edge of the workpiece with the movable mold and the restraining member;
A molding step of moving the movable mold in a direction approaching the fixed mold to a position for molding the workpiece into a predetermined shape;
A mold release step of moving the movable mold in a direction away from the fixed mold;
Comprising
While the moving speed of the movable mold in the contact step is 700 mm / sec or less,
A press molding method in which the moving speed of the movable mold in the molding step is set to 700 mm / sec or more.   The press molding method according to claim 1, wherein a moving speed of the movable mold in the approaching step is set to 700 mm / sec or more.   The press molding method according to claim 1 or 2, wherein a moving speed of the movable mold in the mold releasing step is set to 700 mm / sec or more.   The press molding method according to any one of claims 1 to 3, wherein a bead is formed on the restraining member or the movable mold. Fixed type,
A movable mold that moves between a position where the workpiece is formed in a predetermined shape by approaching the stationary mold and a position where the workpiece can be taken out from the fixed mold;
A restraining member provided on the movable die and restraining the peripheral edge of the workpiece with the fixed die;
A press molding method for molding the workpiece into a predetermined shape using a press molding apparatus comprising:
An approach step of moving the movable mold in a direction approaching the fixed mold;
A contact step of bringing the restraining member into contact with the workpiece and restraining a peripheral edge of the workpiece with the restraining member and the fixed mold;
A molding step of moving the movable mold in a direction approaching the fixed mold to a position for molding the workpiece into a predetermined shape;
A mold release step of moving the movable mold in a direction away from the fixed mold;
Comprising
While the moving speed of the movable mold in the contact step is 700 mm / sec or less,
A press molding method, wherein a moving speed of the movable mold in the molding step is set to 700 mm / sec or more.   The press molding method according to claim 5, wherein a moving speed of the movable mold in the approaching step is set to 700 mm / sec or more.   The press molding method according to claim 5 or 6, wherein a moving speed of the movable mold in the mold releasing step is set to 700 mm / sec or more.   The press molding method according to any one of claims 5 to 7, wherein a bead is formed on the restraining member or the fixed mold.

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