JP2924701B2 - Wrinkle holding method and wrinkle holding device for press machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wrinkle holding method and a wrinkle holding device for a press machine, and more particularly to a technique for preventing a wrinkle holding ring from being damaged due to a moment generated in a wrinkle holding ring during wrinkle holding. It is.

[0002]

[Prior art]

(A) a plurality of cushion pads to which a wrinkle holding load is applied by a wrinkle holding load applying means; and (b) a plurality of cushion pads interposed in parallel between the cushion pad and the wrinkle holding ring to transmit the wrinkle holding load. It has a cushion pin, and presses the peripheral edge of the work between the wrinkle holding ring and the die to hold the wrinkle, and in that state, the wrinkle holding ring and the die move relative to the punch in the press direction. A so-called single action type press machine which draws the work along the punch type forming surface by being made to work, that is, a so-called single action type press machine is widely known. The press described in Japanese Patent Application Laid-Open No. 5-285557 is an example, in which a plurality of cushion pins are placed on a substantially horizontal cushion pad, and a wrinkle holding ring is placed on the cushion pin. A wrinkle press is performed between the die and the die that is lowered from above, and a drawing process is performed along a forming surface of a punch die fixedly disposed inside a wrinkle press ring.

The press described in the above publication also has
(C) a pressure equalizing device for making the transmission loads of the plurality of cushion pins substantially equal to each other, and when the work is wrinkled and held between the wrinkle holding ring and the die mold, variations in the length of the cushion pins and cushions are provided. Regardless of the inclination of the pad or the like, a desired wrinkle holding distribution can be obtained corresponding to the arrangement position of the cushion pin. The pressure equalizer is
For example, the hydraulic cylinder is configured to include a plurality of hydraulic cylinders arranged corresponding to the plurality of cushion pins and the hydraulic chambers are communicated with each other. By setting the state, the transmission loads of the plurality of cushion pins become substantially equal. The hydraulic cylinder is desirably provided on a cushion pad, but may be provided on a cushion pin or the like.

[0004]

However, in such a conventional press machine as well, if a moment is generated in the wrinkle holding ring based on the wrinkle holding load applied from the cushion pin, the wrinkle holding ring may change its posture. In some cases, the wrinkle presser was damaged and the desired press quality could not be obtained. The cause of the moment generated in the wrinkle holding ring is, for example, a misalignment between a contact position of the cushion pin with the wrinkle holding ring in a work inflow direction at the time of drawing and a work clamping position at the time of wrinkle holding. A moment about a center line that is substantially perpendicular and substantially perpendicular to the pressing direction is locally generated, and the work cannot be sufficiently pinched due to the bending deformation of the wrinkle holding ring, or the work is partially hit to cause cracking. There is. Also, if the positions of the plurality of cushion pins that transmit the wrinkle holding load to the wrinkle holding ring are biased, the wrinkle holding load applied to the wrinkle holding ring during the wrinkle holding becomes an eccentric load as a whole and the moment is reduced. As a result, the wrinkle holding ring may be impaired by the inclination or bending deformation of the wrinkle holding ring.

On the other hand, the wrinkle holding load transmitted from the cushion pin to the wrinkle holding ring propagates through the wrinkle holding ring while radiating from the load application point (contact position) to reach the wrinkle holding surface. If the positions of the plurality of cushion pins that are continuous in the circumferential direction of the wrinkle holding ring are too far apart from the dispersion of the wrinkle holding load, a sufficient wrinkle holding cannot be obtained locally and the surface pressure distribution becomes poor. It may be uniform and press quality may be impaired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to generate a local or overall moment in a wrinkle holding ring based on a wrinkle holding load applied from a cushion pin. The object of the present invention is to prevent the wrinkle presser from being damaged. Another object is to obtain a substantially uniform surface pressure distribution in the circumferential direction of the wrinkle holding ring.

[0007]

A first invention for solving the problems is as follows.
(A) a plurality of cushion pads to which a wrinkle holding load is applied by a wrinkle holding load applying means; and (b) a plurality of cushion pads interposed in parallel between the cushion pad and the wrinkle holding ring to transmit the wrinkle holding load. It has a cushion pin, and presses the peripheral edge of the work between the wrinkle holding ring and the die to hold the wrinkle, and in that state, the wrinkle holding ring and the die move relative to the punch in the press direction. by provoking, in blank holding method of a press machine for deep drawing the workpiece along the forming surface of the punch form, (c) the leading
Position of the contact pin against the wrinkle holding ring
When it is on the outer peripheral side of the work clamping pressure position at the time of wrinkle holding
To, due to the moment generated on the basis of the positional deviation so that the pressure ring is not the posture change, the person
On the outer peripheral side of the contact position , the wrinkle holding ring and the die are prevented from approaching by a predetermined amount or more.

[0008]

[0009]

[Operation and Effects of First Invention ie, while the direction of the holding force approaching from the cushion pin die is applied in the contact position, the workpiece clamping position on the inner circumferential side of the contact position In the case, a load in the opposite direction (wrinkle pressing surface pressure or bead forming force) is applied from the die to the die via the work, and the inner periphery is separated from the die and the outer periphery approaches the die with the contact position as a fulcrum. since the direction of the moment is generated in the pressure ring, there since pressure ring against the die in the outer peripheral side of the abutting position has to prevent the approaching a predetermined amount or more. As a result, a change in the posture (bending deformation) of the wrinkle holding ring caused by the above-mentioned moment is prevented, and the wrinkle holding surface pressure at the work clamping position is reduced or inclined with respect to the die mold due to the change in the posture. The wrinkle press is always performed in good condition, such as avoiding
And the desired press quality can be obtained stably
Become like When the cushion pad is almost horizontal and the wrinkle holding ring is placed on it via a cushion pin,
The direction approaching the die is upward, and the direction away from the die is downward.

Although not included in the first invention, when the arrangement position of the plurality of cushion pins for transmitting the wrinkle holding load to the wrinkle holding ring is deviated, it is caused by a moment generated based on the deviation. In order to prevent the posture of the wrinkle holding ring from changing, it is also possible to prevent the wrinkle holding ring and the die from approaching by a predetermined amount or more on the bias side of the cushion pin . In this case, the biased side of the cushion pin causes a moment in the direction in which the biased side approaches the die. However, the biased side prevents the die from approaching the die more than a predetermined amount. Accordingly, it is possible to prevent the wrinkle holding ring from being damaged due to a change in posture (inclination or bending deformation) of the wrinkle holding ring.

[0011]

A second invention for solving the problems is as follows.
(A) a plurality of cushion pads to which a wrinkle holding load is applied by a wrinkle holding load applying means; and (b) a plurality of cushion pads interposed in parallel between the cushion pad and the wrinkle holding ring to transmit the wrinkle holding load. It has a cushion pin, and presses the peripheral edge of the work between the wrinkle holding ring and the die to hold the wrinkle, and in that state, the wrinkle holding ring and the die move relative to the punch in the press direction. by provoking, in the clamp fixture of the press machine for deep drawing the workpiece along the forming surface of the punch form, (c) the leading
Position of the contact pin against the wrinkle holding ring
When it is on the outer peripheral side of the work clamping pressure position at the time of wrinkle holding
To, due to the moment generated on the basis of the positional deviation so that the pressure ring is not the posture change, the person
Distance means is provided between the wrinkle holding ring and the die on the outer peripheral side of the contact position to prevent the two from approaching by a predetermined amount or more.

[0012]

The second invention relates to a wrinkle holding device capable of suitably implementing the wrinkle holding method of the first invention .
Distance means is provided between the wrinkle holding ring and the die mold on the outer peripheral side from the contact position to prevent the two from approaching by a predetermined amount or more, and a moment is generated in the wrinkle holding ring based on the wrinkle holding load. So that the wrinkle retainer ring does not change posture due to the moment.
By a predetermined amount or more of approaching the pressure ring and the die is prevented by distance means, first invention
In the same manner as described above, wrinkle press failure due to a change in the posture of the wrinkle press ring is prevented, and good wrinkle press is always performed, so that desired press quality can be stably obtained.

[0013]

As the distance means, for example, a distance block made of metal is preferably used, but various means such as a hydraulic cylinder and a spring member which can prevent the wrinkle holding ring from approaching the die mold are employed. It is possible.

[0015]

A third aspect of the present invention is to provide
(A) a plurality of cushion pads to which a wrinkle holding load is applied by a wrinkle holding load applying means; and (b) a plurality of cushion pads interposed in parallel between the cushion pad and the wrinkle holding ring to transmit the wrinkle holding load. It has a cushion pin, and presses the peripheral edge of the work between the wrinkle holding ring and the die to hold the wrinkle, and in that state, the wrinkle holding ring and the die move relative to the punch in the press direction. In the wrinkle holding method of the press machine for drawing the work along the forming surface of the punch type, (c) the contact position of the cushion pin with the wrinkle holding ring at the time of the wrinkle holding is performed. When it is on the outer peripheral side of the work clamping pressure position, the wrinkle holding (D) preventing the wrinkle holding ring and the die from approaching by a predetermined amount or more on the outer peripheral side of the contact position so as not to change the posture of the cushion pin in the circumferential direction of the wrinkle holding ring. Are set so that the surface pressure for clamping the work between the die and the die is substantially uniform in the circumferential direction based on the wrinkle holding load transmitted from the cushion pin to the wrinkle holding ring. It is characterized by having done.

[0016]

According to the third aspect of the present invention, similarly to the first aspect, at the position where the cushion pin abuts on the wrinkle retaining ring, a wrinkle retaining load is applied in a direction approaching the die from the cushion pin. On the other hand, at the work clamping position on the inner peripheral side of the contact position, a load in the opposite direction from the die mold via the work (wrinkle holding surface pressure or bead forming force)
When the moment on the inner side is separated from the die and the outer side is approaching the die around the abutment position, a wrinkle holding ring is formed. On the other hand, it was designed to prevent the wrinkle holding ring from approaching more than a predetermined amount.
The change in the posture (bending deformation) of the wrinkle holding ring due to the above moment is prevented, and the wrinkle holding surface pressure at the work clamping position is reduced due to the change in the posture, or the work is inclined with respect to the die mold. The occurrence of cracks due to one-sided collision is avoided.

On the other hand, in the present invention, the interval between the cushion pins in the circumferential direction of the wrinkle holding ring is set such that the work is transferred between the die and the die based on the wrinkle holding load transmitted from the cushion pin to the wrinkle holding ring. Since the clamping pressure is set so as to be substantially uniform in the circumferential direction, good wrinkle holding can be performed even in an intermediate portion between the cushion pins in the circumferential direction.

That is, according to the present invention, a wrinkle holding defect due to a displacement between the contact position of the cushion pin and the work clamping position is prevented, and a wrinkle holding defect in the circumferential direction of the wrinkle holding ring is also prevented. As a result, wrinkle holding is always performed satisfactorily as a whole, and desired press quality can be stably obtained.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the press machine 10 shown in FIG. 1, a bolster 14 to which a punch mold 12 is attached is positioned and fixed substantially horizontally at a predetermined position on a bed 16 while a die mold 1 is mounted.
The slide plate 20 to which the mounting plate 8 is attached is configured to be moved up and down by a lifting drive means (not shown). The bolster 14 is provided with a large number of through holes 26 for disposing the cushion pins 24.
A cushion pad 28 for supporting the cushion pins 24 is disposed below the cushion 4. The cushion pin 24 supports a wrinkle holding ring 30 provided together with the punch mold 12.
Any number is provided at a predetermined position that is predetermined according to the shape or the like. A press die is formed by the punch die 12, the die die 18, and the wrinkle holding ring 30, and is used by being detachably attached to the press machine 10.

The cushion pad 28 has a through hole 26
, A plurality of hydraulic cylinders 32 are provided, and the lower ends of the cushion pins 24 are respectively mounted on piston rods of the hydraulic cylinder 32. The cushion pad 28 can be moved up and down while being guided by a guide (not shown), and is constantly urged upward by an air cylinder 34 functioning as a wrinkle pressing load applying means. When the mold 18 is lowered and brought into contact with the wrinkle holding ring 30 across the work 36, the air cylinder 3
4, a wrinkle holding load having a size corresponding to the pressure receiving area of the air chamber 38 and the air pressure is applied to the wrinkle holding ring 30 from the cushion pad 28 via the cushion pin 24,
The peripheral portion of the work 36 is pressed according to the wrinkle pressing load and pressed. The air pressure in the air chamber 38 is manually or automatically adjusted by the air pressure adjusting means 40 in accordance with a desired wrinkle holding load, and the upper surface of the wrinkle holding ring 30, that is, the wrinkle holding surface has a circumferential groove 42. On the other hand, the groove 4 is formed on the wrinkle holding surface of the die 18.
2, a ridge 44 is provided at a position corresponding to 2, and a bead 46 is formed on the work 36. Then, the die 18 is further lowered while the peripheral edge of the work 36 is wrinkled and pressed, and the die 18 and the wrinkle holding ring 30 are relatively moved in the pressing direction with respect to the punch 12. The work 36 is drawn along the forming surface of the punch mold 12.

The hydraulic chambers of the plurality of hydraulic cylinders 32 communicate with each other through a communication oil passage 48, and the hydraulic pressure is affected by variations in the length of the cushion pin 24, inclination of the cushion pad 28, and the like. Instead, the hydraulic pressure adjusting means 50 automatically or manually adjusts the pistons of all the hydraulic cylinders 32 involved in the wrinkle press at the time of the wrinkle press so that the pistons are driven into a neutral state. Therefore, the transmitted load by each cushion pin 24 at the time of wrinkle holding becomes substantially equal, and a desired wrinkle holding load distribution can be obtained corresponding to the arrangement position of the cushion pin 24. These hydraulic cylinder 32, communication oil passage 48, and hydraulic adjustment means 50
The pressure equalizing device 52 is constituted by these. The pressure equalizing device 52, the wrinkle holding ring 30, the cushion pin 24, the cushion pad 28, the air cylinder 3
4 and the like constitute an equalizing cushion device 54 as a wrinkle holding device.

On the other hand, in a portion of the wrinkle holding ring 30 where the position of the cushion pin 24 is set on the outer peripheral side of the bead 46 forming portion, the position supported by the cushion pin 24, that is, the wrinkle holding load is reduced. A distance block 58 made of a metal material is attached as a distance means to the upper surface of the outer peripheral side portion 56 from the contact position to which the voltage is applied, and the upper end of the distance block 58 is brought into contact with the die 18 to form a wrinkle holding ring. The outer peripheral side portion 56 of the die 30 and the die 18 are prevented from approaching by a predetermined amount or more. As a result, local change in the posture (bending deformation) of the wrinkle holding ring 30 is prevented, and good wrinkle holding is always performed, so that desired press quality can be stably obtained.

Referring specifically to FIG. 2, which is an enlarged view of the wrinkle holding portion on the left side of FIG. 1, the contact position X of the cushion pin 24 is on the outer peripheral side of the bead 46 (left side in FIG. 2). In this case, at the contact position X, an upward wrinkle pressing load f approaching the die 18 is applied, while at the bead forming portion, a bead forming force B for forming the bead 46 acts downward and the bead forming is performed. Since the reaction force A of the clamping force acts on the portion where the work 36 is clamped on the inner peripheral side portion (right side in FIG. 2) of the portion, the contact position X is locally applied to the wrinkle holding ring 30. A clockwise clockwise moment in FIG. 2 is generated as a fulcrum. For this reason, if there is no distance block 58, as shown in FIG.
0 is locally bent and deformed, and in the case of (a), the bead 46 is not sufficiently formed and the surface pressure of the wrinkle holder is reduced, so that a desired tension cannot be obtained at the time of drawing, and molding defects such as wrinkles are formed. On the other hand, when the work 36 protrudes to the outer peripheral side from the wrinkle holding ring 30 as shown in FIG. There is a possibility that the tension at the time of processing becomes excessive and a molding failure such as a crack may occur.

On the other hand, in this embodiment, the distance block 58 is provided on the outer peripheral portion 56 on the outer peripheral side of the contact position X.
Is provided to prevent the wrinkle holding ring 30 and the die 18 from approaching by a predetermined amount or more, so that the posture change (bending deformation) of the wrinkle holding ring 30 due to the moment is prevented. . The length (height) dimension of the distance block 58 is set such that the upper surface of the wrinkle holding ring 30, that is, the wrinkle holding surface 60 is maintained substantially parallel to the wrinkle holding surface 62 of the die 18 during drawing. As described above, both wrinkle holding surfaces 60,
By maintaining the parallel state of 62, a wrinkle holding defect due to a change in the posture of the wrinkle holding ring 30 is avoided.

In the present embodiment, the portion where the bead 46 is formed and the portion where the work 36 is pressed on the inner peripheral side thereof are the work pressing position. Bead 4 on the upper surface of wrinkle holding ring 30
6 is lower than the inner peripheral portion that functions as the wrinkle holding surface 60, and no surface pressure is generated. Note that wrinkle holding can be performed only by forming the bead 46 on the work 36, or wrinkle holding can be performed only by pressing the work 36 without forming the bead 46.

Here, the arrangement position of the distance block 58 will be examined. First, Distance Block 5
By 8 is brought into contact with the die 18, when the downward force exerted on the pressure ring 30 through the distance blocks 58 from the die 18 and f _D, the wrinkle holding force f, the bead molding force B , And the reaction force A of the clamping pressure have the relationship of the following equation (1) from the balance of the forces. Further, the dimension from the contact position X to the center of the load of the force f _D in the workpiece inflow direction perpendicular to the pressing direction is L _D ,
Dimension L _B from the contact position X to the load center of the bead molding force B, and the dimension from the abutting position X to the load center of the reaction force A of the clamping pressure and L _A, the following formula from the moment balance (2 ) Is obtained. Then, by substituting the equation (2) into the equation (3) and eliminating the reaction force A, the following equation (3) is obtained. When this is rewritten, the dimension L _D is expressed by the following equation (4). Note that the reaction force A of the clamping force is obtained by setting the wrinkle pressing surface pressure on the wrinkle pressing surface 60 to σ, and in a direction perpendicular to the bead 46 (work inflow direction)
The length of the wrinkle holding surface 60 is S, and the cushion pin 24 in a direction parallel to the bead 46 (the circumferential direction of the wrinkle holding ring 30).
Letting the separation distance be W, A = σSW.

(Equation 1)

On the other hand, the tension T for drawing in the work 36 during the drawing process is represented by μ representing the friction coefficient of the wrinkle holding surface 60 when the work passes through the work, R _{B being the} bending and returning force of the bead 46, and the angle between the wrinkle holding portion and the forming surface. Assuming that the bending / returning force of the portion is R _R , it is expressed by the following equation (5). Moreover, the the force f _D is applied, when the plate thickness t of the workpiece 36 by the surface pressure σ after molding completion the beads 46 and is when compressed by Delta] t, bent by the tension T unbending force R _B When it becomes effective, the bead shape tends to return to the original shape. In that case,
If f-f _D ≧ R _B, never bead shape returns to the original, that without the surface pressure σ becomes 0 with the molding condition of proper bead 46 is maintained always good wrinkle holding Done. Therefore, if the dimension L _D is determined so as to satisfy the above-mentioned ff _D ≧ R _B , in other words, to satisfy the following expression (6), stable wrinkle holding is always performed.

(Equation 2)

As described above, the above expression (6) must be satisfied.
However, the stability of wrinkle retainers and the reproducibility of press quality were confirmed.
Is the first priority condition for maintaining_D<R_Bso
Also its bending and bending return force R_BAs shown in FIG.
When the die shape becomes loose and gentle, the die 18
The wrinkle holding ring 30 is separated, and the surface pressure σ and the force f
_DIs reduced, if at least the following expression (7) is satisfied,
A bead 46 is formed. In this case, a complete bead 4
6 cannot be formed, and the surface pressure σ becomes 0,
The state in which the distance block 58 contacts the die 18
In this state, the clearance between the wrinkle holding surfaces 60 and 62 is substantially
A constant and substantially constant bending / returning force R _BPlace
A bead 46 having a fixed size is formed. in this way,
Equation (7) is satisfied and ff_D<R_BThat is,
Dimension L to satisfy (8)_DIf you set a stable
Wrinkle holding is performed. This is Distance Block 5
In the second priority condition to stabilize the wrinkle presser by 8
To generate the tension T by the bead forming force B
In addition, stable drawing with less tension fluctuation can be performed.
Wear. Whether to use the first priority condition or the second priority condition
It can be arbitrarily selected according to the wrinkle holding condition of each part,
In the holding ring 30, both priority conditions
There may be a mixture of the case blocks 58.

(Equation 3)

The above is a configuration for preventing a wrinkle press defect due to a positional deviation of a load in the workpiece inflow direction. Next, a configuration for preventing a wrinkle press defect in the circumferential direction of the wrinkle press ring 30 will be described. I do. In the pressure equalizing cushion device 54, the arrangement interval (the separation distance W) of the cushion pins 24 in the circumferential direction of the wrinkle holding ring 30 is based on the wrinkle holding load f transmitted from the cushion pin 24 to the wrinkle holding ring 30. Work 3
6, the surface pressure at the wrinkle holding surface 60.
Are set to be substantially uniform in the circumferential direction.

FIG. 4 is a view for explaining the surface pressure distribution in the circumferential direction of the wrinkle holding ring 30. A wrinkle holding load f is transmitted to each of three boss portions 64 with which the cushion pin 24 is brought into contact. The transmitted wrinkle holding load f is
Wrinkle holding ring 3 while radially dispersing from boss 64
The light propagates through 0 and reaches the wrinkle holding surface 60. Boss 64
A relatively large surface pressure σ ₀ is generated only at the portion where the boss portion 64 is provided on the lower surface provided with
The surface pressures σ ₁ , σ ₂ , and σ gradually become smaller and the distribution area becomes larger in the direction of the 部分 portion, the ｄ portion of the thickness d, and the wrinkle holding surface 60. The surface pressures propagating from the boss portions 64 overlap, resulting in a substantially constant surface pressure distribution irrespective of the position of the boss portions 64. It should be noted that the total loads {σ ₀ , Σ} of the surface pressures σ ₀ , σ ₁ , σ ₂ , σ due to the propagation from one boss portion 64.
σ ₁ , Σσ ₂ , and Σσ are wrinkle holding loads f. Further, in FIG. 4, upward arrows indicating the surface pressures σ ₀ , σ ₁ , σ ₂ , and σ are omitted in the load propagation portions from the boss portions 64 on both sides, and only the surface pressure distribution is shown.

As described above, in the present embodiment, the separation distance W is
In relation to the thickness d of the wrinkle holding ring 30, the wrinkle holding surface 6
Since the surface pressure distribution at 0 is preset so as to be substantially uniform, the wrinkle holding defect in the circumferential direction of the wrinkle holding ring 30 is prevented, and the good wrinkle holding is performed even in the intermediate portion between the cushion pins 24. . That is, according to the present embodiment, the wrinkle holding defect based on the displacement between the contact position X of the cushion pin 24 and the work clamping position (the positions of the beads 46 and the wrinkle holding surfaces 60 and 62) is caused by the distance block 58.
In addition, since the separation distance W of the cushion pin 24 is appropriately set, the wrinkle holding defect in the circumferential direction of the wrinkle holding ring 30 is also prevented.
Wrinkle holding will be always performed well as a whole,
The desired press quality can be obtained stably.

In the case where wrinkle holding is performed mainly by generating the tension T by the bead 46, the bead 46 is formed well even if the surface pressure σ is partially low. It is not necessary to set the separation distance W and the thickness d of the cushion pin 24 so that σ is substantially uniform.

If the arrangement positions of the plurality of cushion pins 24 are deviated, a moment is generated based on the deviation, and the wrinkle holding ring 30 may change posture and cause a wrinkle holding defect. For example, in the case where the position indicated by “○” in FIG. 5 is the contact position X, that is, the support position supported by the cushion pin 24, the wrinkle holding ring 30
When the x-y coordinates are set with the center of gravity of the center of gravity as the origin 0 and the unit length between the cushion pins 24 (the arrangement interval of the hydraulic cylinders 32) is a, the moments M _{1 to} M _{4 in} each quadrant are This is the same as applying the wrinkle holding load f to the position indicated by “●” in FIG. Further, the total of them, that is, the moment M _T of the entire wrinkle holding ring 30 is the same as that of applying the wrinkle holding load f to the position indicated by “○” in FIG. 6, and the portion of the fourth quadrant faces upward. Is pressed. Therefore, in the portion of the fourth quadrant, a distance means similar to the distance block 58 is arranged at least on the outer peripheral side of the work clamping position, and the distance between the wrinkle holding ring 30 and the die 18 is equal to or more than a predetermined amount. By blocking the approach of
If so the blank holding surfaces 60 and 62 to maintain the parallel state, the blank-holding failure caused by the moment M _T is Ru is prevented.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the present invention can be embodied in other forms.

For example, in the above-described embodiment, the distance block 58 is attached to the wrinkle holding ring 30, but may be attached to the die 18 or the slide plate 20 or the like. In the above embodiment, the distance block 58 attached to the wrinkle holding ring 30 may be brought into contact with another member such as the slide plate 20 which moves integrally with the die 18.

Further, the mode of the pressure equalizing device 52 can be changed as appropriate, and the present invention can be applied to a device which does not include a pressure equalizing device and which does not have a pressure equalizing device.

In the above-described embodiment, the air cylinder 34 is used as the wrinkle holding load applying means. However, various other wrinkle holding load applying means such as a spring or a fluid flow resistance may be employed.

In the press machine 10 of the above-described embodiment, the punch die 12 is provided at a fixed position. However, a punch die and a wrinkle holding ring are disposed above a fixed die die, and these are moved downward. The configuration of the press machine can be changed as appropriate, for example, it can be moved to perform drawing.

Although not specifically exemplified, the present invention can be embodied with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a press machine that includes a wrinkle holding device according to an embodiment of the second invention, in which the wrinkle holding method according to the first and third inventions can be suitably implemented.

FIG. 2 is a view showing dimensions of each part for mechanically analyzing a left wrinkle holding portion in the press machine of FIG. 1;

FIG. 3 is a cross-sectional view showing a state in which the bead is gentle and the wrinkle holding ring and the die are separated from each other in the press machine of FIG.

FIG. 4 is a view for explaining a circumferential surface pressure distribution of a wrinkle holding ring and a propagation state of a wrinkle holding load in the press machine of FIG. 1;

FIG. 5 is a diagram showing an example of a shape of a wrinkle holding ring and an arrangement of cushion pins in the press machine of FIG. 1;

FIG. 6 is a diagram illustrating a moment generated in a wrinkle holding ring in the case of FIG. 5;

FIG. 7 is a cross-sectional view showing a wrinkle holding state when a distance block is removed from the press machine of FIG. 1;

[Explanation of symbols]

 10: Press machine 12: Punch type 18: Die type 24: Cushion pin 30: Wrinkle holding ring 34: Air cylinder (wrinkle holding load applying means) 36: Work 54: Equalizing cushion device (Wrinkle holding device) 58: Distance block (Distance means)

Claims (3)

(57) [Claims] 1. A cushion pad to which a wrinkle holding load is applied by a wrinkle holding load applying means, and a plurality of cushions which are interposed in parallel between the cushion pad and the wrinkle holding ring to transmit the wrinkle holding load, respectively. A pin, and presses the peripheral edge of the work between the wrinkle holding ring and the die to hold the wrinkle, and in this state, moves the wrinkle holding ring and the die relative to the punch in the pressing direction. In the wrinkle holding method of a press machine for drawing the work along the forming surface of the punch type, the cushion pin abuts on the wrinkle holding ring.
The position is on the outer peripheral side of the work clamping position at the time of wrinkle holding
In this case, a predetermined amount of the wrinkle holding ring and the die mold at a position more outer than the contact position so that the wrinkle holding ring does not change its posture due to a moment generated based on the displacement. A method for holding wrinkles of a press machine, characterized in that the approach of the wrinkles is prevented. 2. A cushion pad to which a wrinkle holding load is applied by a wrinkle holding load applying means, and a plurality of cushions which are interposed in parallel between the cushion pad and the wrinkle holding ring to transmit the wrinkle holding load, respectively. A pin, and presses the peripheral edge of the work between the wrinkle holding ring and the die to hold the wrinkle, and in this state, moves the wrinkle holding ring and the die relative to the punch in the pressing direction. In the wrinkle holding device of the press machine for drawing the work along the forming surface of the punch type, the cushion pin abuts on the wrinkle holding ring.
The position is on the outer peripheral side of the work clamping position at the time of wrinkle holding
In order to prevent the wrinkle holding ring from changing its posture due to a moment generated based on the positional deviation , both the wrinkle holding ring and the die mold are disposed on the outer peripheral side from the contact position. A wrinkle holding device for a press machine, further comprising a distance means for preventing an approach of a predetermined amount or more. 3. A cushion pad to which a wrinkle holding load is applied by a wrinkle holding load applying means, and a plurality of cushions interposed in parallel between the cushion pad and the wrinkle holding ring to transmit the wrinkle holding load, respectively. A pin, and presses the peripheral edge of the work between the wrinkle holding ring and the die to hold the wrinkle, and in this state, moves the wrinkle holding ring and the die relative to the punch in the pressing direction. In the wrinkle holding method of the press machine for drawing the work along the forming surface of the punch type, the contact position of the cushion pin with the wrinkle holding ring is a work clamping position at the time of the wrinkle holding. The wrinkling press ring changes its posture due to the moment generated due to the displacement when it is on the outer peripheral side. While preventing the wrinkle holding ring and the die from approaching by a predetermined amount or more on the outer peripheral side of the contact position so as not to be in contact with each other, the arrangement interval of the cushion pins in the circumferential direction of the wrinkle holding ring is reduced. A press wherein the surface pressure for clamping the work between the die and the die is set to be substantially uniform in the circumferential direction based on the wrinkle holding load transmitted from the cushion pin to the wrinkle holding ring. How to hold down wrinkles on machines.