JP2011156548A - Press machine, and press method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a press machine in which the bouncing of an object to be pressed is prevented from occurring when a holding unit comes to a stop and a die is separated from the holding unit, and thus not only the accuracy of positioning the object to be pressed is improved, but also a decrease in the productivity is avoided; and to provide a press method. <P>SOLUTION: The press machine 10 includes: a lower die 20 having a punch 21 formed on the upper surface thereof; an upper die 30 having a die 31 formed on the lower surface thereof, and so configured as to make a vertical approach to/separation from the lower die 20; a holding unit 27 disposed in the lower die 20 in such a manner as to slide vertically therein; fluid cylinders 41 disposed in the lower die 20, for biasing the lower surface of the holding unit 27 to the side of the upper die 30; and elastic bodies 51 for biasing, when the upper die 30 comes up from the lower die 20 and the die 31 is separated from the holding unit 27, the upper surface of the holding unit 27 to the side of the lower die 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pressing apparatus and a pressing method, and more particularly to a technique for press-molding a workpiece such as a work panel in the pressing apparatus.

2. Description of the Related Art Conventionally, in a press apparatus for forming a car body of an automobile, a workpiece such as a work panel is placed between a lower mold having a punch formed on the upper surface and an upper mold having a die formed on the lower surface. In this state, a technique is used in which the workpiece is press-molded (for example, draw molding, bending molding, punching molding, etc.) by moving the upper mold close to and away from the lower mold. Specifically, the lower die is provided with holding means (blank holder, work holder, etc.) slidable in the vertical direction, and the upper die is held in a state where the workpiece is sandwiched between the holding means and the die. The workpiece is press-molded by bringing it close to the lower mold.
And in these press devices, in order to obtain a reaction force against the force with which the holding means is pressed from the die, and in order to buffer the impact generated when the punch and the die press the workpiece, An elastic member may be disposed between the lower mold and the holding means (for example, Patent Document 1 and Patent Document 2).

JP 2008-173678 A Japanese Utility Model Publication No. 6-14955

The prior art will be specifically described with reference to FIGS. FIG. 18 to FIG. 20 are cross-sectional views showing states before, during, and after forming in the press device according to the related art.
The press device shown in FIG. 18 performs press molding (drawing), and is arranged with a lower die having a punch formed on the upper surface, and facing the lower die (upward in FIG. 18). An upper die having a die formed on the lower surface, holding means arranged to be slidable in the vertical direction with respect to the lower die, and an elastic member interposed between the lower die and the holding means to support the holding means And a gas cylinder as a member.

  In the press apparatus, a plate-like work panel, which is a workpiece, is placed between the punch and the die. At this time, the gas cylinder is somewhat compressed by the load of the holding means and the workpiece. Further, at this stage, as shown in FIG. 18, the workpiece is positioned so as to have a gap with respect to the upper surface of the punch. When the workpiece is formed by a press device, the upper die is first lowered as shown by the arrow in FIG. 18, and the peripheral portion of the workpiece is sandwiched between the lower surface of the die and the upper surface of the holding means. To do.

  Thereafter, the upper die is further lowered to bring the workpiece into contact with the upper surface of the punch, and then the workpiece is pressed against the upper surface of the punch to be deformed, thereby pressing the workpiece as shown in FIG. (Drawing) is performed. At this time, the holding means moves down together with the upper mold while compressing the gas cylinder while holding the state where the workpiece is held.

  Thereafter, the upper die is raised as shown by the arrow in FIG. 19, and the upper die is separated from the lower die as shown in FIG. At this time, since the gas cylinder expands due to the internal pressure, the holding means rises together with the upper mold while maintaining the state of sandwiching the workpiece until the die is separated. The holding means stops when the gas cylinder returns to the length before molding, and at the same time, the die is separated from the holding means.

  As described above, according to the press apparatus according to the related art, in the process in which the upper die moves up and strokes from the bottom dead center to the top dead center, the holding means stops and at the same time the die is separated from the holding means. At this time, if the die and the holding means are stroked at a certain speed or more, even if the holding means stops, the workpiece may bounce due to inertia and move as indicated by the arrow in FIG. When the workpiece bounces in this way, there is a problem in that the positioning accuracy of the workpiece deteriorates, leading to a decrease in productivity.

  Therefore, the present invention prevents the workpiece from bouncing when the holding means stops and at the same time the die separates from the holding means, improves the positioning accuracy of the workpiece, and prevents a decrease in productivity. A press apparatus and a press method are provided.

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

  That is, in claim 1, a lower mold having a punch formed on the upper surface, an upper mold having a die formed on the lower surface and configured to be close to and away from the lower mold in the vertical direction, and the lower mold A holding means configured to be slidable in the vertical direction and configured to be held by sandwiching a workpiece inserted between the die and the die, and disposed in the lower mold, A pressing device including at least one elastic member that urges the holding means toward the upper die side, wherein the upper die in a lowered state is raised from the lower die side, and the die is held by the holding device. At the time of separating from the means, at least one elastic body is provided to urge the upper surface of the holding means toward the lower mold side.

  According to a second aspect of the present invention, at least one of the elastic members includes a first cushion portion that urges against the lower surface of the holding means, and the lower surface of the holding means after the first cushion portion is compressed. And a second cushion portion that is urged with a force larger than that of the first cushion portion.

  According to a third aspect of the present invention, the two-stage elastic member includes a fluid cylinder that houses a small-diameter piston as the first cushion portion and a large-diameter piston as the second cushion portion.

  In Claim 4, It is a press method which press-molds the said to-be-processed object in the press apparatus of Claim 2 or Claim 3, Comprising: The said to-be-processed object was mounted in the upper surface of the said holding means In the first step, the upper mold is lowered in the direction of the lower mold until the die contacts the holding means, and the first cushion portion urges the lower surface of the holding means toward the upper mold side. A second step in which the upper mold is lowered toward the lower mold in a state where the workpiece is sandwiched between the lower surface of the die and the upper surface of the holding means; A third step in which the upper die is lowered to the bottom dead center in the direction of the lower die while pressing the lower surface of the means toward the upper die, and the workpiece is press-molded; and the second cushion The upper die is urged against the upper die side by the lower portion of the holding means. A fourth step of ascending in a direction opposite to the mold; and the first cushion portion urges the lower surface of the holding means toward the upper mold side, and at the same time, the elastic body moves the upper surface of the holding means toward the lower mold side The upper mold rises in a direction opposite to the lower mold until the die is separated from the holding means, and after the die is separated from the holding means, And a sixth step in which the mold rises to the top dead center in the direction opposite to the lower mold.

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

  According to the present invention, when the holding means is stopped and at the same time the die is separated from the holding means, the workpiece is prevented from bouncing, the workpiece positioning accuracy is improved, and the productivity is prevented from being lowered. it can.

Sectional drawing which showed the state before shaping | molding in the press apparatus which concerns on 1st embodiment. Sectional drawing which showed the state during shaping | molding in the press apparatus which concerns on 1st embodiment. Sectional drawing which showed the state after shaping | molding in the press apparatus which concerns on 1st embodiment. Sectional drawing which showed the state before shaping | molding in the press apparatus which concerns on 2nd embodiment. Sectional drawing which showed the state after the 1st process in the press apparatus which concerns on 2nd embodiment. Sectional drawing which showed the state after the 2nd process in the press apparatus which concerns on 2nd embodiment. Sectional drawing which showed the state after the 3rd process in the press apparatus which concerns on 2nd embodiment. Sectional drawing which showed the state after the 4th process in the press apparatus which concerns on 2nd embodiment. Sectional drawing which showed the state after the 5th process in the press apparatus which concerns on 2nd embodiment. Sectional drawing which showed the state after the 6th process in the press apparatus which concerns on 2nd embodiment. (A1) to (a3) are diagrams showing the two-stage fluid cylinder in the press device according to the second embodiment, and (b) is a diagram showing the relationship between the stroke according to the second embodiment and the load of the two-stage fluid cylinder. Diagram. Sectional drawing which showed the state before shaping | molding in the press apparatus which concerns on a 2nd Example. Sectional drawing which showed the state during shaping | molding in the press apparatus which concerns on a 2nd Example. Sectional drawing which showed the state after shaping | molding in the press apparatus which concerns on a 2nd Example. Sectional drawing which showed the state before shaping | molding in the press apparatus which concerns on a 3rd Example. Sectional drawing which showed the state in the process of shaping | molding in the press apparatus which concerns on a 3rd Example. Sectional drawing which showed the state after shaping | molding in the press apparatus which concerns on a 3rd Example. Sectional drawing which showed the state before shaping | molding in the press apparatus which concerns on a prior art. Sectional drawing which showed the state during shaping | molding in the press apparatus which concerns on a prior art. Sectional drawing which showed the state after shaping | molding in the press apparatus which concerns on a prior art.

Next, embodiments of the invention will be described.
It should be noted that the technical scope of the present invention is not limited to the following examples, but broadly covers the entire scope of the technical idea that the present invention truly intends, as will be apparent from the matters described in the present specification and drawings. It extends.

[First embodiment]
First, the press apparatus 10 which concerns on 1st embodiment of this invention is demonstrated using FIG. In the present specification, for convenience of explanation, the upper side in each drawing is the upper side, the lower side is the lower side, the right side is the right side, the left side is the left side, the front side is the front side, and the back side is the rear side. .

As shown in FIG. 1, a press device 10 according to the present embodiment is provided with a lower die 20 having a punch 21 formed on the upper surface, and opposed to the lower die 20 (upward in FIG. 1). And an upper die 30 having a die 31 formed on the lower surface.
Specifically, the lower mold 20 is fixed on a base (not shown), and a recess 22 is formed on the upper surface. A punch 21 projecting upward is formed at the approximate center of the recess 22. On the other hand, the upper mold 30 is disposed on a platen (not shown) configured to be close to and away from the base in the vertical direction. A die 31 slightly larger than the punch 21 in plan view is formed so that the punch 21 can be inserted in the approximate center of the lower surface of the upper mold 30.

Further, the pressing device 10 includes holding means (for example, a blank holder) 27 that is arranged to be slidable in the vertical direction with respect to the lower mold 20.
Specifically, the holding means 27 is formed in substantially the same shape as the concave portion 22 in plan view, and a hole 27a having the same shape as the punch 21 is opened in the vertical direction. The holding means 27 is fitted into the recess 22 so as to be slidable in the vertical direction with respect to the lower mold 20 in a state where the punch 21 is inserted into the hole 27a. When the upper mold 30 comes close to the lower mold 20, the upper mold 30 and the lower mold 20 are formed by the upper holding surface 31 a that is the lower surface of the die 31 and the lower holding surface 27 b that is the upper surface of the holding means 27. It is comprised so that the to-be-processed object W which is a plate-shaped work panel inserted in between can be clamped.

Between the lower mold 20 and the holding means 27, the fluid cylinders 41, 41, which are elastic members that support the holding means 27 and urge the lower surface of the holding means 27 toward the upper mold 30 side.・ ・ Is inserted.
Specifically, each of the fluid cylinders 41, 41,... Includes cylinder portions 41a, 41a, and pistons 41b, 41b,. The pistons 41b, 41b,... Are slidably inserted into the cylinder portions 41a, 41a, etc., and a gas such as nitrogen is contained inside the fluid cylinders 41, 41,. Have been supplied. The fluid cylinders 41, 41,... Configured as described above are disposed at the bottom of the concave portion 22 with the pistons 41b, 41b,.
In each drawing in this specification, eight fluid cylinders 41 are shown, but the fluid cylinders 41 are arranged side by side not only in the left-right direction but also in the front-rear direction. That is, the fluid cylinders 41, 41... Support the lower surface of the holding means 27 as a whole.

The fluid cylinders 41, 41,... Compress when a load is applied from above to the pistons 41b, 41b, and when the loads on the pistons 41b, 41b,. It is comprised so that it may expand | extend with the internal pressure of the gas supplied inside. Thus, the holding means 27 is supported by the fluid cylinders 41, 41,.
In addition, the holding means 27 supported by the fluid cylinders 41, 41,... It is comprised so that it may become higher than the height position of the upper surface of 21.

  As described above, when the press device 10 according to the present embodiment is provided with the fluid cylinders 41, 41,... At the same time, the punch 21 and the die 31 are configured to buffer the impact generated when the workpiece W is press-molded.

  In the present embodiment, the fluid cylinder 41, which is a gas cylinder, is used as an elastic member that biases the holding means 27. However, the elastic member includes a resin product such as urethane, a hydraulic cylinder, and a spring. Or a combination of these may be used as long as the member has elasticity against a load. The number of the elastic members is not limited regardless of the embodiment.

Further, in the press apparatus 10 according to the present embodiment, when the upper die 30 in the lowered state is lifted from the lower die 20 side and the die 31 is separated from the holding means 27, the holding means 27 Are provided with elastic bodies (in the present embodiment, absorbers) 51, 51,.
Specifically, fixed blocks 23, 23,... Are fixed to the front, rear, left, and right ends of the upper portion of the lower mold 20, and elastic bodies 51, 51,. It is set up. The elastic bodies 51, 51... Are arranged with the piston rod extending downward, and the upper surface of the holding means 27 is moved by the piston rod when the holding means 27 is raised by the fluid cylinders 41, 41. It is arrange | positioned so that it may urge to the lower mold | type 20 side.
In each drawing in the present specification, two elastic bodies 51 are described, but the number of elastic bodies 51 can be changed as appropriate according to the size of the holding means 27 and the like. That is, the number of elastic bodies 51 is not limited and can be changed according to the embodiment of the press device 10.

[Pressing method]
A pressing method in the pressing apparatus 10 configured as described above will be described with reference to FIGS.
When the plate-like workpiece W is drawn by the press device 10, first, the workpiece W is placed between the punch 21 and the die 31. At this time, the fluid cylinders 41, 41... Are somewhat compressed by the load of the holding means 27 and the workpiece W. Further, at this stage, as shown in FIG. 1, the workpiece W is placed on the holding means 27 and is positioned so as to have a gap with respect to the upper surface of the punch 21. Further, the piston rods of the elastic bodies 51, 51... Are compressed by the upper surface of the holding means 27. Then, the upper die 30 is lowered as shown by the arrow in FIG. 1, and the peripheral portion of the workpiece W is moved between the upper holding surface 31 a that is the lower surface of the die 31 and the lower holding surface 27 b that is the upper surface of the holding means 27. Hold it.

  Thereafter, the upper die 30 is further lowered to bring the workpiece W into contact with the upper surface of the punch 21, and then the workpiece W is further pressed against the upper surface of the punch 21 to be deformed into the shape of the punch 21. As shown in FIG. 2, press forming of the workpiece W (drawing in this embodiment) is performed. At this time, the holding means 27 descends together with the upper mold 30 while holding the workpiece W sandwiched, and compresses the fluid cylinders 41, 41,... Until reaching the bottom dead center shown in FIG. In this process, the piston rods of the elastic bodies 51, 51... Extend as the holding means 27 descends, and when the elastic bodies 51, 51. It is separated from the elastic bodies 51.

Thereafter, the upper die 30 is raised as shown by the arrow in FIG. 2, and the upper die 30 is separated from the lower die 20 as shown in FIG. 3. At this time, since the fluid cylinders 41, 41,... Are extended by the internal pressure, the holding means 27 rises together with the upper mold 30 while maintaining the state in which the workpiece W is held until the die 31 is separated.
At this time, in the press apparatus 10 according to the present embodiment, when the die 31 is separated from the holding means 27 as described above, the elastic bodies 51, 51. It is configured to be biased toward the 20 side. For this reason, the holding means 27 begins to decelerate from the moment when the piston rods of the elastic bodies 51, 51... Come into contact with each other, and at the same time, the die 31 is separated from the holding means 27. The holding means 27 that has been gradually decelerated stops when the fluid cylinders 41, 41,... Return to their pre-molding length.

  As described above, according to the press device 10 according to the present embodiment, in the process in which the upper mold 30 moves up and strokes from the bottom dead center to the top dead center, before the holding means 27 stops, the elastic bodies 51, 51, The holding means 27 can be sufficiently decelerated by. For this reason, even if the holding means 27 stops, the workpiece W does not bounce due to inertia as in the prior art, and the workpiece W can be stopped at a predetermined position as shown in FIG. It is. That is, it is possible to improve the positioning accuracy of the workpiece W after press molding, and to prevent the productivity of the press-formed product from being lowered.

[Second Embodiment]
Next, the 1st Example of the press apparatus 110 which concerns on 2nd embodiment of this invention is demonstrated using FIG. In the present embodiment, the case where the workpiece W1 is drawn by the press device 110 will be described. Note that, in the description of the press device according to the following embodiment, portions common to the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 4, the press device 110 according to the present embodiment is a two-stage elastic member as an elastic member between the lower mold 20 and the holding means 27 in addition to the configuration of the press device 10 according to the embodiment. Two-stage fluid cylinders 141, 141... Are inserted. The two-stage fluid cylinders 141, 141,... Have small diameter pistons 141c, 141c,... As a first cushion portion that supports the holding means 27 and urges against the lower surface of the holding means 27. Further, the two-stage fluid cylinders 141, 141,... Are urged with a larger force than the small diameter pistons 141c, 141c,... After the small diameter pistons 141c, 141c,. As the second cushion part, large diameter pistons 141b, 141b,... Are provided. In other words, the two-stage fluid cylinders 141, 141,... Are provided with small-diameter pistons 141c, 141c,... The large-diameter pistons 141b, 141b,.

  In detail, as shown in FIGS. 11 (a1) to (a3), the large-diameter pistons 141b, 141b,... Are slidably inserted into the cylinder portions 141a, 141a,. 141c, 141c,... Are slidably inserted into the large-diameter pistons 141b, 141b,. Further, a gas such as nitrogen is supplied into the two-stage fluid cylinders 141, 141,. That is, as shown in FIG. 11B, the two-stage fluid cylinders 141, 141... Are compressed with a small force when the small-diameter pistons 141c, 141c,. (The stroke ST1 shown in FIGS. 11 (a1) to (a3) and (b)), and then the large-diameter pistons 141b, 141b... Having a large cross-sectional area are compressed with a large force (from FIG. 11 (a1)). The stroke ST2 shown in (a3) and (b) is configured. When the load is reduced, the large-diameter pistons 141b, 141b,... Are first expanded by the internal pressure of the gas supplied to the inside, and then the small-diameter pistons 141c, 141c,. It is composed.

  As described above, the two-stage fluid cylinders 141, 141,... Are arranged at the bottom of the recess 22 together with the fluid cylinders 41, 41,. 141c, 141c... Are arranged facing upward. Here, the total length of the cylinder portion 141a and the large-diameter piston 141b of the two-stage fluid cylinder 141 is substantially the same as the total length of the cylinder portion 41a and the piston 41b of the fluid cylinder 41. That is, when a load is applied to the two-stage fluid cylinders 141, 141, and the fluid cylinders 41, 41, and the like from above by a horizontal plane, the horizontal plane contacts the large-diameter piston 141b and simultaneously contacts the piston 41b. It is configured as follows. In other words, the horizontal plane compresses the small-diameter pistons 141c, 141c,... In the two-stage fluid cylinders 141, 141, and then the large-diameter pistons 141b, 141b,. .. And the pistons 41b, 41b,... Of the fluid cylinders 41, 41,. In this way, the holding means 27 is supported by the two-stage fluid cylinders 141, 141... And the fluid cylinders 41, 41.

  Each figure in this specification shows two two-stage fluid cylinders 141, but the two-stage fluid cylinders 141 can be arranged side by side not only in the left-right direction but also in the front-rear direction. The number is not limited. Further, depending on the type and size of press molding and the elasticity of the two-stage fluid cylinder 141, it is possible to adopt a configuration in which only the two-stage fluid cylinder 141 is disposed without the fluid cylinder 41 being disposed.

  As described above, in the press device 110 according to the present embodiment, the holding means 27 is formed by the die 31 by disposing the two-stage fluid cylinders 141, 141... And the fluid cylinders 41, 41. At the same time, the punch 21 and the die 31 are configured to buffer the impact generated when the workpiece W1 is press-molded.

  In the present embodiment, a two-stage fluid cylinder 141 that is a gas cylinder is used as a two-stage elastic member that urges the holding means 27. However, the two-stage elastic member may be a urethane having a different size. It may be composed of resin products, hydraulic cylinders having different inner diameters, springs having different elastic coefficients, and the like, and any member having two-stage elasticity with respect to the load can be applied. The number of the two-stage elastic members is not limited regardless of the embodiment.

[Pressing method]
A pressing method in the press apparatus 110 configured as described above will be described with reference to FIGS.
In the pressing method in the press apparatus 110 according to the present embodiment, the upper mold 30 is the lower mold 20 until the die 31 comes into contact with the holding means 27 in a state where the workpiece W1 is placed on the upper surface of the holding means 27. The first step of lowering in the direction, the small diameter pistons 141c, 141c,... Urges the lower surface of the holding means 27 toward the upper mold 30, and the upper holding surface 31a, which is the lower surface of the die 31, and the holding means 27. The second step in which the upper die 30 is lowered toward the lower die 20 with the workpiece W1 held between the lower holding surface 27b, which is the upper surface, and the large-diameter pistons 141b, 141b,. A third step in which the upper die 30 is lowered to the bottom dead center in the direction of the lower die 20 and press-molding the workpiece W1, while urging the lower surface of the upper die 30 toward the upper die 30; 141b, 141b,... The upper die 30 is lifted in the opposite direction to the lower die 20 while being biased toward the lower die 20, and the small diameter pistons 141c, 141c,... Attach the lower surface of the holding means 27 to the upper die 30 side. At the same time, the upper body 30 is opposite to the lower mold 20 until the die 31 moves away from the holding means 27 while the elastic bodies 51, 51... Urge the upper surface of the holding means 27 toward the lower mold 20 side. And a sixth step in which the upper die 30 rises to the top dead center in a direction opposite to the lower die 20 after the die 31 is separated from the holding means 27.

Each of the above steps will be described in order.
When the plate-like workpiece W1 is drawn by the press device 110, first, the workpiece is processed between the punch 21 and the die 31 with the upper die 30 and the lower die 20 separated from each other as shown in FIG. Place the object W1. At this time, as shown in FIG. 4, the lower surface of the holding means 27 abuts only on the small diameter pistons 141c, 141c,... Of the two-stage fluid cylinders 141, 141, and the large diameter pistons 141b, 141b,. It does not contact the piston 41b of the cylinder 41. Further, the small-diameter pistons 141c, 141c, ... of the two-stage fluid cylinders 141, 141, ... are somewhat compressed by the load of the holding means 27 and the workpiece W1. Further, at this stage, as shown in FIG. 4, the workpiece W <b> 1 is positioned so as to have a gap with respect to the upper surface of the punch 21. Further, the piston rods of the elastic bodies 51, 51... Are compressed by the upper surface of the holding means 27.

  Thereafter, in the first step, the upper die 30 is lowered as shown by the arrow in FIG. 4 with the workpiece W1 placed on the upper surface of the holding means 27. Then, as shown in FIG. 5, the die 31 is brought into contact with the holding means 27, and the peripheral portion of the workpiece W <b> 1 is formed by the upper holding surface 31 a that is the lower surface of the die 31 and the lower holding surface 27 b that is the upper surface of the holding means 27. Is pinched.

  Thereafter, in the second step, the small-diameter pistons 141 c, 141 c... Urge the lower surface of the holding means 27 toward the upper mold 30, and the upper holding surface 31 a that is the lower surface of the die 31 and the upper surface of the holding means 27. The upper die 30 is further lowered in the direction of the lower die 20 in a state where the workpiece W1 is held between the lower holding surface 27b. Then, as shown in FIG. 6, the workpiece W1 is brought into contact with the upper surface of the punch 21, and at the same time, the lower surface of the holding means 27 is brought into contact with the large-diameter pistons 141b, 141b,. It is. In this process, the piston rods of the elastic bodies 51, 51... Extend as the holding means 27 descends.

  Thereafter, in the third step, the large-diameter pistons 141b, 141b,... And the pistons 41b, 41b,... Urge the lower surface of the holding means 27 toward the upper mold 30, while the upper mold 30 is moved to the lower mold 20. Lower in the direction. Further, by pressing the workpiece W1 against the upper surface of the punch 21 and deforming it into the shape of the punch 21, the press-working of the workpiece W1 (in the present embodiment, the drawing molding process) is performed as shown in FIG. is there. At this time, the holding means 27 descends together with the upper die 30 while holding the workpiece W1 in a sandwiched state until the bottom dead center shown in FIG. 7 is reached, and the large-diameter pistons 141b, 141b,. -Compress 41b ... In the process, the holding means 27 is separated from the elastic bodies 51, 51... When the elastic bodies 51.

  Thereafter, in the fourth step, the large-diameter pistons 141b, 141b,... And the pistons 41b, 41b,... Urge the lower surface of the holding means 27 toward the upper mold 30, while the upper mold 30 is moved to the lower mold 20. Raise in the opposite direction. In other words, since the large-diameter pistons 141b, 141b,... And the pistons 41b, 41b,... Are extended by the internal pressure, the holding means 27 maintains the state in which the workpiece W1 is held until the die 31 is separated. 8, when the large-diameter pistons 141b, 141b,... And the pistons 41b, 41b,... Return to their pre-molding state, the holding means 27 has the large-diameter pistons 141b, 141b,. 41b...

  Thereafter, in the fifth step, the small-diameter pistons 141c, 141c,... Urge the lower surface of the holding means 27 toward the upper mold 30, and the elastic bodies 51, 51,. The upper die 30 is raised in the direction opposite to the lower die 20 until the die 31 is separated from the holding means 27 while being biased toward the side 20. As shown in FIG. 9, when the small-diameter pistons 141 c, 141 c... Return to the state before molding, the die 31 is separated from the holding means 27.

  At this time, in the press apparatus 110 according to the present embodiment, when the die 31 is separated from the holding means 27 as described above, the elastic bodies 51, 51. It is configured to be biased toward the 20 side. For this reason, the holding means 27 begins to decelerate from the moment when the piston rods of the elastic bodies 51, 51... Come into contact with each other, and at the same time, the die 31 is separated from the holding means 27. The holding means 27 that has been gradually decelerated stops when the two-stage fluid cylinders 141, 141,... Return to their pre-molding length.

  Thereafter, in the sixth step, after the die 31 is separated from the holding means 27, the upper die 30 is raised in the direction opposite to the lower die 20 to the top dead center as shown in FIG.

As described above, in the press device 110 according to the present embodiment, the small-diameter pistons 141c, 141c, which are the first cushion portions of the two-stage fluid cylinders 141, 141, and the large-diameter pistons, which are the second cushion portions. 141b, 141b... Is configured to urge the lower surface of the holding means 27 toward the upper mold 30.
Specifically, as shown in FIGS. 11 (a1) to 11 (a3) and FIG. 11 (b), the two-stage fluid cylinder 141 has a small sectional area with a small force in the stroke ST1 in which the small-diameter piston 141c having a small sectional area is compressed. In the stroke ST2 in which the large-diameter piston 141b having a large diameter is compressed, it is compressed with a large force. In other words, the two-stage fluid cylinder 141 urges the upper surface of the holding means 27 toward the lower mold 20 with a small force in the stroke ST1, and the upper surface of the holding means 27 toward the lower mold 20 with a large force in the stroke ST2. Energize.

That is, as shown in FIG. 11 (b), just before the die 31 is separated from the holding means 27 in the stroke ST1 of the fifth step, the small diameter pistons 141c, 141c,... Since the lower surface of 27 is urged toward the upper mold 30, the force with which the elastic bodies 51, 51... Urge the upper surface of the holding means 27 toward the lower mold 20 can also be reduced. That is, the number of the elastic bodies 51, 51,... Can be reduced as compared with the above embodiment, so that the cost can be reduced.
On the other hand, when press-forming the workpiece W1 in the stroke ST2 of the third step, the large diameter pistons 141b, 141b,... And the pistons 41b, 41b,. As shown in FIG. 11B, the required load similar to that of the above-described embodiment can be ensured because the bias is applied to the upper mold 30 side.

  As described above, according to the press device 110 according to the present embodiment, in the process in which the upper die 30 moves up and strokes from the bottom dead center to the top dead center, before the holding means 27 stops, a smaller number than the above embodiment. The holding means 27 can be sufficiently decelerated by the elastic bodies 51. For this reason, even if the holding means 27 is stopped, the workpiece W1 does not bounce due to inertia unlike the prior art, and the workpiece W1 can be stopped at a predetermined position as shown in FIG. It is. That is, the positioning accuracy of the workpiece W1 after press molding can be improved with a simpler configuration, and the productivity of the press-formed product can be prevented from being lowered.

[Another embodiment]
Next, a second example of the press device 110 according to the present embodiment will be described with reference to FIGS. In this embodiment, the case where the workpiece W2 is bent by the press device 110 will be described. In the embodiment described below, the only difference from the first embodiment is the processed shape of the workpiece, and the configuration of the pressing device 110 and the pressing method itself are substantially the same. The description of the process is omitted.

  When bending the plate-like workpiece W2 in the press device 110, first, the workpiece is processed between the punch 21 and the die 31 with the upper die 30 and the lower die 20 being separated as shown in FIG. Place the object W2. Further, the workpiece W2 is pressed against the upper surface of the punch 21 and bent along the shape of the punch 21, so that the workpiece W2 is press-formed (bending in this embodiment) as shown in FIG. is there. Thereafter, after the die 31 is separated from the holding means 27, the upper die 30 is raised in the direction opposite to the lower die 20 to the top dead center as shown in FIG.

Next, a third example of the press device 110 according to the present embodiment will be described with reference to FIGS. 15 to 17. In the present embodiment, a case where the workpiece W3 is punched with the press device 110 will be described.
When the plate-like workpiece W3 is punched and formed in the press device 110, first, the workpiece is processed between the punch 21 and the die 31 with the upper die 30 and the lower die 20 being separated as shown in FIG. Place the object W3. Further, by pressing the workpiece W3 against the upper surface of the punch 21 and extracting it into the shape of the upper surface of the punch 21, press forming of the workpiece W3 (in this embodiment, punching) is performed as shown in FIG. is there. Thereafter, after the die 31 is separated from the holding means 27, the upper die 30 is raised in the direction opposite to the lower die 20 to the top dead center as shown in FIG.

  As described above, the press apparatus 110 according to the present embodiment can be applied to the case where other press formation is performed, such as when the workpiece W2 (W3) is bent (pulled). That is, in the process in which the upper mold 30 is raised and stroked from the bottom dead center to the top dead center, before the holding means 27 stops, the holding means 27 is reduced by a smaller number of elastic bodies 51. Can be sufficiently slowed down. For this reason, even if the holding means 27 is stopped, the workpiece W2 (W3) does not bounce due to the inertia as in the prior art, and the workpiece W2 (in the predetermined position as shown in FIG. 14 (FIG. 17)). It is possible to stop W3). That is, the positioning accuracy of the workpiece W2 (W3) after press molding can be improved with a simpler configuration, and the productivity of the press-formed product can be prevented from being lowered.

DESCRIPTION OF SYMBOLS 10 Press apparatus 20 Lower mold | type 21 Punch 30 Upper mold | type 31 Die 41 Fluid cylinder 51 Elastic body W Workpiece

Claims (4)

A lower mold with a punch formed on the upper surface;
An upper die having a die formed on the lower surface and configured to be close to and away from the lower die in the vertical direction;
A holding means configured to be slidable in the vertical direction on the lower mold and configured to be held by sandwiching a work piece interposed between the die and the die;
At least one elastic member disposed on the lower mold and biasing the holding means toward the upper mold,
At least one elastic body for urging the upper surface of the holding means toward the lower mold when the upper mold in the lowered state rises from the lower mold side and the die is separated from the holding means; Prepare
A press apparatus characterized by that. At least one of the elastic members includes a first cushion portion that urges against the lower surface of the holding means, and the first cushion portion compresses the lower surface of the holding means after the first cushion portion is compressed. Arranged as a two-stage elastic member comprising a second cushion portion biased with a large force,
The press apparatus according to claim 1, wherein The two-stage elastic member is composed of a fluid cylinder that houses a small-diameter piston as the first cushion portion and a large-diameter piston as the second cushion portion, respectively.
The press apparatus according to claim 2, wherein A press method for press-molding the workpiece in the press device according to claim 2 or 3,
A first step in which the upper mold is lowered in the direction of the lower mold until the work piece is placed on the upper surface of the holding means until the die contacts the holding means;
In the state where the first cushion portion urges the lower surface of the holding means toward the upper mold side and the workpiece is sandwiched between the lower surface of the die and the upper surface of the holding means, the upper mold is the lower mold A second step of descending in the direction of
The second cushion portion urges the lower surface of the holding means toward the upper mold side, and the upper mold descends to the bottom dead center in the direction of the lower mold, and press-molds the workpiece. Three processes,
A fourth step in which the upper mold rises in a direction opposite to the lower mold while the second cushion portion urges the lower surface of the holding means toward the upper mold;
The first cushion portion urges the lower surface of the holding means toward the upper mold side, and at the same time, the elastic body urges the upper surface of the holding means toward the lower mold side, while the die is separated from the holding means. Until the upper mold rises in the opposite direction to the lower mold,
After the die is separated from the holding means, the upper die rises to the top dead center in a direction opposite to the lower die, and a sixth step.
A pressing method characterized by the above.

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