JP2009195956A - Wrinkle holding mechanism that can achieve dynamic control in drawing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wrinkle holding mechanism which has a simple structure, can vary a wrinkle holding force of a flange part in a blank independently of drawing with a punch and can achieve dynamic control of the wrinkle holding force depending on a change (reduction) in area of the flange part of the blank in a drawing process. <P>SOLUTION: The wrinkle holding mechanism comprises: a spring, the top of which is fixed vertically to a die block; a spring receiver which fixes the lower end face of the spring and can be freely lifted and lowered; a spring receiver lifting/lowering means which lifts and lowers the spring receiver; a regulating plate on which the spring lifting/lowering means is mounted and which fixes the lower end of a post and conveys the downward force by the spring to the post; and a wrinkle holder which fixes the upper end of the post and imparts a wrinkle holding force to the flange part of the blank through the wrinkle holder. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a press working (drawing) apparatus for a metal plate, and in particular, a drawing operation in which the wrinkle pressing force of a blank flange portion can be controlled during the drawing independently of the drawing operation by a punch and a die. The present invention relates to a wrinkle pressing mechanism capable of dynamic control in processing.

Drawing is an operation for obtaining a seamless bottomed cylindrical shape from a flat sheet metal (blank), and one of them is a method of deforming a sheet metal by a punch and a die using a press machine. In this method, when the diameter of the blank is D and the diameter of the punch is d _p , m = d _p / D is called the aperture ratio, and its inverse β = D / d _p is called the aperture ratio. Thus, the maximum value of the drawing ratio that can be drawn from the flat plate at one time without causing wrinkling or breakage of the material or the semi-finished product is called a limit drawing ratio (LDR). The limit drawing ratio (LDR) is affected by the material, the shape of the drawing die, dimensions, lubrication conditions, and the like.

In the drawing process using a press machine, the process is performed by a punch and a die. For a relatively thick plate (t / D> 0.04-0.05, t: plate thickness, D: blank diameter) and a relatively shallow aperture (d _p / D≈20 / 21) It is not necessary, but wrinkle holding is necessary when deep drawing thin plates. When the wrinkle holding force increases, the squeezing force increases and the required energy increases. Generally, therefore, it is necessary to make the wrinkle holding force as small as possible unless wrinkles are generated. The wrinkle holding force is selected to be higher for thinner plates, for materials with higher deformation resistance, and for higher drawing ratios. Thus, in drawing using a press machine, how to increase the limit drawing ratio (LDR) is the key to shortening the process and increasing productivity. .

  In drawing processing of a thin metal plate by a drawing machine (press machine), the area of the blank flange portion (wrinkle holding portion) changes due to the flow of metal as the processing progresses, that is, the punch stroke progresses. . It is necessary to control the wrinkle holding force corresponding to the change (decrease) in the area of the flange portion of the blank with high accuracy. If the wrinkle holding force is insufficient, the blank is wrinkled. If the wrinkle holding force is excessive, the drawn product is broken.

  Conventionally, in drawing processing by a press machine that obtains aircraft parts, automobile parts, electrical equipment parts, equipment, etc., when a material that is inferior in formability, such as an aluminum alloy, is targeted, the limit drawing ratio (LDR) is low. It is necessary to divide the pressing process into a plurality of processes, and there are problems in productivity and cost.

  Thus, in order to increase the limit drawing ratio (LDR), it is necessary to change the wrinkle holding force in accordance with the change (decrease) in the area of the flange portion of the blank corresponding to the progress of drawing. is there.

  However, in the conventional configuration in which the spring is mounted on the back surface of the wrinkle presser, the spring is compressed as the punch stroke progresses, and the wrinkle presser force is increased as the area of the blank flange changes (decreases). There is a problem that it tends to increase and break the processed product easily. Further, when the spring is mounted on the die side, it is very difficult to dynamically control the wrinkle pressing force independently of the pressing force of the punch in the conventional mold configuration.

  In addition, when the wrinkle holding force is applied to the flange portion of the blank by the fluid pressure mechanism, the fluid pressure mechanism is suitable for obtaining quick displacement at a constant pressure, but the wrinkle holding force can be reduced with high accuracy with a simple device configuration. It is not suitable for control that changes force dynamically.

On the other hand, a metal thin plate press die and a press forming method that dynamically change the wrinkle holding force of the blank portion in the drawing have been proposed (see Patent Document 1).
JP 2004-249365 A

  In the prior art disclosed in the above-mentioned Patent Document 1, the wrinkle holding load adjusting means is on the same base as the punch. It is not the structure which changes the wrinkle pressing load loaded between pressing dies independently of the machining process by the punch.

  In addition, the prior art disclosed in Patent Document 1 is considered to be based on a hydraulic mechanism in view of the aspect of FIG. 17 in the same document, but in the case of a hydraulic mechanism, it is suitable for obtaining a quick displacement with a constant pressure. However, it is not suitable for changing wrinkle holding force dynamically by changing pressure with high accuracy with a simple device configuration. In addition, the wrinkle holding load adjusting mechanism to which 4 to 8 hydraulic cylinders are mounted has a problem that the apparatus is not only large and complicated but also requires a high cost, such as requiring a separate hydraulic power source. Furthermore, an apparatus that requires four to eight hydraulic cylinders has a limit in reducing the size of the press machine.

  The present invention has a simple structure and can change the wrinkle holding force of the blank flange portion independently of the punching drawing process, and also wrinkles according to the change (reduction) of the blank flange area in the drawing process. An object of the present invention is to provide a wrinkle pressing mechanism capable of dynamic control of the pressing force and also suitable for downsizing of the apparatus.

  The invention according to claim 1 for solving the above-mentioned problems is a spring whose top portion is fixed to the die block in a vertical direction, a spring receiver which fixes the lower end surface of the spring and which can be raised and lowered, and the spring receiver. A spring receiving elevating means for elevating and lowering, an adjustment plate for mounting the spring elevating means and fixing a lower end portion of the post to transmit a downward force by the spring to the post, and an upper end portion of the post A wrinkle pressing mechanism capable of dynamic control in drawing, characterized by having a wrinkle pressing holder that is fixed and applies a wrinkle pressing force to the flange portion of the blank through the wrinkle pressing.

  The invention according to claim 2 is the wrinkle holding mechanism capable of dynamic control in the drawing process according to claim 1, wherein the spring receiving elevating means is an adjusting screw rotatably supported on the adjusting plate and screwed with the spring receiving. It is.

  According to the present invention, the wrinkle holding force of the blank flange portion can be dynamically changed independently of the punching process with an extremely simple structure. The wrinkle holding force can be dynamically controlled, the drawing can be performed with a high limit drawing ratio (LDR), the drawing depth can be greatly increased, and a low-cost drawing product can be provided with high productivity.

  In addition, the wrinkle holding mechanism capable of dynamic control in the drawing process of the present invention has a simple structure, which enables downsizing of the press machine and provides an inexpensive press machine. Furthermore, since the wrinkle holding force can be changed dynamically independently of punching, the wrinkle holding force that is not entangled with the punch pushing force can be set as an independent parameter, and a higher degree of drawing ( Contributes to the construction of a control system for plastic working.

  The wrinkle holding mechanism capable of dynamic control in the drawing process of the present invention is mounted in a space below a die of a press machine, and by changing the height (axial dimension) of a compression spring, an accurate wrinkle holding force can be obtained. Applies to the flange part.

  1 to 5 show the structure of a wrinkle holding mechanism capable of dynamic control in the drawing process of the present invention. FIG. 1 is a perspective view showing a longitudinal section of a main part of a wrinkle pressing mechanism capable of dynamic control in drawing processing according to the present invention, and FIG. 2 is a perspective view showing an entire wrinkle pressing mechanism capable of dynamic control in drawing processing of the present invention. FIG. 3 is a longitudinal sectional view showing the entire wrinkle pressing mechanism capable of dynamic control in drawing processing of the present invention, and FIG. 4 is a perspective view showing members involved in transmission of wrinkle pressing force by a spring (compression spring). FIG. 5 is a perspective view showing the arrangement of springs and posts.

  In FIG. 1 to FIG. 5, reference numeral 1 denotes a punch, which is displaced in the vertical direction by a driving mechanism (not shown), and draws the blank 3 into a seamless bottomed cylindrical shape in cooperation with the die 2. 3-1 is a flange portion of the blank 3. Reference numeral 4 denotes an upper die block, and reference numeral 5 denotes a lower die block. The upper die block 4 fixes and supports the die 2 together with the lower die block 5 as shown in FIG. As shown in FIG. 3, the lower die block 5 has a hollow portion at the lower portion thereof, and stores a spring 6, a spring receiver 7, and an adjusting screw 8 therein.

  In this embodiment, the springs 6 (compression springs) are arranged at four locations as shown in FIG. The top position of the spring 6 is fixed to the ceiling of the cavity at the lower part of the lower die block 5, and the lower end of the spring 6 is fixed to the spring receiver 7. As shown in FIGS. 1 and 3, the spring receiver 7 is screwed together with an adjusting screw 8 which is an embodiment of the spring receiver lifting and lowering means by a screwing portion 8-1. As shown in FIGS. 1 and 3, the lower portion of the adjusting screw 8 is a hollow 14 having a hexagonal cross section in this embodiment, and is driven under rotation control by a driving source (not shown) such as a pulse motor. It can be rotated by a hexagonal stem that fits into the hollow 14.

  When the adjusting screw 8 rotates, the spring receiver 7 screwed with the adjusting screw 8 moves up and down and changes the axial dimension of the spring 6. Since there is a linear relationship between the change in the axial dimension of the spring 6 and the force generated thereby, the force generated by the spring 6 is controlled with high accuracy using the rotation speed of the adjusting screw 8 as an operating parameter. Can do. On the other hand, as shown in FIGS. 1 and 3, the adjustment screw 8 is rotatably fitted to the stepped portion of the adjustment plate 9 and is fixed in the vertical direction to cope with changes in the axial dimension of the spring 6. The force to transmit is transmitted to the adjustment plate 9 via the spring receiver 7. Further, a thrust bearing may be inserted at the abutting portion between the lower part of the adjusting screw 8 and the adjusting plate 9 to reduce friction.

  As the lifting means for the spring receiver 7, in addition to the adjusting screw 8 in this embodiment, the lower surface of the spring receiver 7 is an inclined surface, and an inclined block 7 that is slidable with the inclined surface is disposed. It is also possible to adopt means such as a means for moving the spring receiver 7 up and down by displacing it, a link mechanism, a rack and pinion combination, a hydraulic cylinder, or the like.

  In this embodiment, the adjustment screw 8 screwed with the spring receiver 7 is used as the spring receiver lifting / lowering means because of the simplicity of the structure, the lifting accuracy, the ease of operation, and the like.

As shown in FIGS. 1, 4, and 5, in this embodiment, the lower ends of the four posts 10 are fixed to the adjustment plate 9. Transmit the acting force to the upper part. As shown in FIGS. 1, 4, and 5, the upper end of the post 10 is fixed to the wrinkle holding holder 11. Reference numeral 12 denotes a wrinkle presser, which is inserted between the wrinkle presser holder 11, the upper die block 4, and the die 2, as shown in FIGS. 1 to 5. Thus, the downward force corresponding to the change in the axial dimension of the spring 6 is transmitted as spring receiver 7 → adjusting screw 8 → adjusting plate 9 → post 10 → wrinkle holding holder 11 → wrinkle holding 12. Thus, as shown in FIGS. 1 and 3, the flange portion 3-1 of the blank 3 is pressed between the wrinkle presser 12 and the top of the die 2 by a downward force corresponding to the change in the axial dimension of the spring 6. Is done.
In FIGS. 2 and 3, reference numeral 13 denotes a punch block on which the punch 1 is fixed. As a means for detecting the wrinkle holding force, for example, a means for inserting a strain gauge between the wrinkle holding holder 11 and the wrinkle presser 12 can be employed.

Next, an operation when the blank 3 is drawn by a press machine equipped with a wrinkle pressing mechanism capable of dynamic control in the drawing process of the present invention will be described.
First, as shown in FIG. 7, the press (punch 1) is positioned at the top dead center. At this time, as shown in FIG. 7, the wrinkle presser 12 is moved in the horizontal direction and removed. Next, as shown in FIG. 6, a blank guide 16 is set on the upper surface of the upper die block 4 according to the outer diameter of the blank 3, and the blank 3 is placed so as to match the blank guide 16. As shown in FIG. 6, the blank guide 16 is composed of two metal plates that are slightly thinner than the blank 3 and can be displaced along the longitudinal direction of the guide presser 17. The interval between the V-shaped parts facing is adjusted. The blank guide 16 makes the center point of the plane of the blank 3 coincide with the axial center of the punch 1 and the die 2.

  Next, as shown in FIG. 8, the wrinkle presser 12 is horizontally inserted between the lower surface of the wrinkle presser holder 11 and the upper surface of the blank 3, and then, as shown in FIG. 9 and FIG. 15 descends, and the slide block 19 is displaced in the horizontal direction by the inclined surface 18 of the drive bar 15 to sandwich the blank 3. In this state, the adjusting screw 8 is rotated by a motor (not shown), and the axial dimension of the spring 6 is set to a desired value. Alternatively, the desired value can be set in advance, and the desired wrinkle pressing force can be applied to the blank 3 as the drive bar 15 is lowered. As a result, the blank 3 is pressed with a predetermined force between the lower surface of the wrinkle retainer 12 and the top of the die 2. As the drawing process proceeds, the wrinkle holding force is dynamically controlled.

  Thereafter, according to a predetermined algorithm, the punch 1 is lowered at a predetermined force and speed, and the state shown in FIGS. 1 and 3 is obtained. Corresponding to the descending amount of the punch 1, the metal of the flange portion 3-1 flows toward the die 2, and the area of the flange portion 3-1 decreases. After the press reaches the bottom dead center, the wrinkle pressing force by the adjusting screw 8 is released, and the drive bar 15 rises as shown in FIGS. 11 and 12, and the slide block 19 is moved by the slope on the opposite side of the drive bar 15. Is horizontally displaced in the opposite direction to the above, and the wrinkle retainer 12 is raised. The wrinkle presser 12 can be lifted by the drive bar 15 being lifted with the wrinkle presser force applied to the flange portion 3-1.

  Since the amount of decrease in the area of the flange portion 3-1 corresponding to the amount of lowering of the punch 1 can be predicted by a prior experiment, the wrinkle holding force against the flange portion 3-1 corresponding to the amount of lowering of the punch 1 can be estimated. The adjustment operation is performed by changing the axial dimension of the spring 6 (compression spring) using the rotation speed of the adjustment screw 8 as an operation parameter. In this way, the wrinkle pressing force according to the progress of the drawing process on the blank 3 due to the lowering of the punch 1 is controlled.

The perspective view which shows the principal part longitudinal cross-section of the wrinkle pressing mechanism which can be dynamically controlled in the drawing process which concerns on one Example of this invention. The perspective view which shows the whole wrinkle pressing mechanism which can be dynamically controlled in the drawing processing which concerns on one Example of this invention. 1 is a longitudinal sectional view showing an entire wrinkle holding mechanism capable of dynamic control in drawing processing according to an embodiment of the present invention. The perspective view which shows the member concerned in transmission of the wrinkle pressing force by the spring (compression spring) of the wrinkle pressing mechanism which can be dynamically controlled in the drawing process which concerns on one Example of this invention. The perspective view which shows arrangement | positioning of the spring of a wrinkle pressing mechanism which can be dynamically controlled in the drawing processing which concerns on one Example of this invention, and a post | mailbox The perspective view which shows the blank guide in the case of the blank set in the wrinkle holding | maintenance mechanism which can be dynamically controlled in the drawing process which concerns on one Example of this invention The perspective view which shows the state of the top dead center of the press in the wrinkle pressing mechanism which can be dynamically controlled in the drawing process which concerns on one Example of this invention. The perspective view which shows the state by which the wrinkle presser was penetrated in the wrinkle presser mechanism which can be dynamically controlled in the drawing processing which concerns on one Example of this invention. The front view which shows the state when the slide block is displaced in the horizontal direction by the descent of the drive bar in the wrinkle pressing mechanism capable of dynamic control in the drawing processing according to one embodiment of the present invention. The front view which shows the state of a drive bar when a press descend | falls to the bottom dead center vicinity in the wrinkle pressing mechanism which can be dynamically controlled in the drawing process which concerns on one Example of this invention. The front view which shows the state when displacing a slide block to the horizontal direction opposite side by the raise of a drive bar in the wrinkle pressing mechanism which can be dynamically controlled in the drawing process which concerns on one Example of this invention. The front view which shows the state when the wrinkle pressing mechanism which can be dynamically controlled in the drawing process which concerns on one Example of this invention displaces a slide block to the horizontal direction opposite side by the raise of a drive bar, and makes wrinkle pressing free.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Punch 2 Dies 3 Blank 3-1 Blank flange part 4 Upper die block 5 Lower die block 6 Spring 7 Spring receiver 8 Adjustment screw (spring receiver raising / lowering means)
8-1 Screwing section 9 Adjustment plate 10 Post 11 Wrinkle holding holder 12 Wrinkle holding 13 Punch block 14 Hollow 15 Drive bar 16 Blank guide 17 Guide holding 18 Slope in drive bar 19 Slide block

Claims (2)

  Mounted on the die block is a spring whose vertical position is fixed to the top of the die block, a spring receiver that fixes the lower end surface of the spring and that can be raised and lowered, a spring receiver that raises and lowers the spring receiver, and the spring raising and lowering means And an adjustment plate for fixing the lower end of the post and transmitting a downward force by the spring to the post, and fixing the upper end of the post and applying a wrinkle holding force to the blank flange through the wrinkle holding A wrinkle holding mechanism capable of dynamic control in drawing processing, comprising a wrinkle holding holder applied to the portion.   2. The wrinkle holding mechanism capable of dynamic control in drawing according to claim 1, wherein the spring receiving elevating means is an adjusting screw rotatably supported on the adjusting plate and screwed with the spring receiving.

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