Drawing die

Abstract

The utility model provides a drawing die which comprises a female die, a male die and a blank holder, and the female die is concaved inwards to form a cavity used for forming a blank; a convex part is formed on the convex die, and the convex part can enter the cavity so as to be matched with the cavity to draw the blank into a preset shape; the blank holder is arranged between the female die and the male die, the blank holder can be matched with the female die to press the blank, and the protruding part can penetrate through the middle of the blank holder to press the blank into the cavity; wherein an elastic lifting pin is arranged on the side, opposite to the female die, of the blank holder, the elastic lifting pin is provided with an elastic lifting part which protrudes out of the blank holder and can stretch out and draw back elastically, when the blank holder and the female die are matched to press a blank, the elastic lifting part is pressed back to the blank holder by the blank, and when the female die is separated from the blank, the elastic lifting part can jack the blank up from the blank holder. And therefore, a gap for air to enter can be formed between the blank and the lug boss in the demolding process. According to the drawing die, the production cost and the repair rate are reduced, and the production efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of automobile molds, and in particular to drawing molds. Background Art

[0002] The outer panel of the front cover of the automobile mold frequently has hollows and pits during the drawing process. In the related technology, a process method of adding vent holes at the low points of the main molding surfaces of the upper and lower mold surfaces of the drawing mold is usually adopted to eliminate the vacuum generated during the drawing process and avoid hollows and pits caused by the vacuum during drawing.

[0003] This process can solve the problem of hollows and dark pits, but the long-term wear of the mold will lead to collapsed angles around the exhaust holes, and pore oil pits will be formed on the surface of the parts under the action of drawing oil. The production process has very strict requirements on the thickness of the oil film on the sheet metal surface, which must be uniform and between 1.5 and 2.0 mg / ㎡. When the sheet metal oil film exceeds 2.0 mg / ㎡, pore oil pits will be formed on the surface of the parts under the action of drawing oil, and the rework rate is as high as 15%, which seriously affects the surface quality of the front cover outer panel. In addition, the drawing oil on the mold surface needs to be cleaned frequently during the production process, about once every 180 to 200 pieces. Calculated based on a single batch of 2,000 pieces, the mold is cleaned 10 times on average per batch, with a downtime loss of nearly 40 minutes. The production rhythm can only be controlled at 7 to 8 times / minute, and the production efficiency is low. Utility Model Content

[0004] To at least partially solve the above-mentioned problems, an embodiment of the present application provides a drawing die, which includes a die, a punch and a pressure ring. The die is concave to form a cavity for forming a blank; the punch is formed with a protrusion, which can enter the cavity to cooperate with the cavity to draw the blank into a predetermined shape; the pressure ring is arranged between the die and the punch, and the pressure ring can cooperate with the die to press the blank, and the protrusion can pass through the middle of the pressure ring to press the blank into the cavity; wherein, a spring pin is arranged on the side of the pressure ring opposite to the die, and the spring pin has an elastic top portion that protrudes from the pressure ring and can be elastically retractable. When the pressure ring cooperates with the die to press the blank, the elastic top portion is pressed back to the pressure ring by the blank, and when the die is separated from the blank, the elastic top portion can lift the blank from the pressure ring, so that a gap for air to enter can be formed between the blank and the protrusion during demolding.

[0005] In some embodiments, there are multiple ejector pins, and the multiple ejector pins are distributed along the circumference of the blank holder ring.

[0006] In some embodiments, the number of the ejector pins is four, and the four ejector pins are respectively arranged at the four corners of the pressure ring.

[0007] In some embodiments, a draw bead groove is provided on the blank holder ring, and the ejector pin is provided on one side of the draw bead groove away from the middle of the blank holder ring.

[0008] In some embodiments, the ejector pin is 60 to 100 mm away from the drawbead groove.

[0009] In some embodiments, the concave die is the upper die of the drawing die, the convex die is the lower die of the drawing die, and the sum of the ejection forces of the multiple ejector pins is greater than the gravity of the blank.

[0010] In some embodiments, a screw hole is opened on the pressure ring, and the ejector pin is arranged in the screw hole. The depth of the screw hole is greater than the length of the cylindrical shell of the ejector pin.

[0011] In some embodiments, the ejector pin is vertically disposed on the blank holder.

[0012] In some embodiments, the top of the spring is 13±2 mm above the surface of the blank holder.

[0013] In some embodiments, the drawing die is one of a car front cover outer panel drawing die, a car top cover outer panel drawing die, a car four-door outer panel drawing die, and a car trunk lower outer panel drawing die.

[0014] The drawing die provided by the embodiment of the present application is provided with a spring ejector pin on the blank holder. During the demoulding process, the spring ejector pin can lift the drawn blank for a distance, thereby eliminating the vacuum between the blank and the raised portion, avoiding the hollow pit caused by the vacuum and the pore oil pit caused by opening a hole at a low point on the main mold surface of the mold; and the spring ejector pin can be installed by only opening a screw hole on the existing drawing die, so it is convenient for low-cost improvement of old equipment. The drawing die provided by the embodiment of the present application reduces production costs and rework rates, and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 It is a structural schematic diagram of a part of the structure of a drawing die provided in an embodiment of the present application at an angle;

[0017] Figure 2 is a structural schematic diagram of a partial structure of a drawing die provided in an embodiment of the present application from another angle;

[0018] Figure 3 It is a schematic structural diagram of a blank holder ring of a drawing die provided in an embodiment of the present application;

[0019] Figure 4It is a schematic structural diagram of the ejector pin of the drawing die provided in an embodiment of the present application.

[0020] The reference numerals are as follows:

[0021] 10. Punch; 11. Raised portion; 20. Binder ring; 21. Ejector pin.

[0022] It should be understood that the size of each part shown in the accompanying drawings is not drawn according to the actual proportional relationship. In addition, the same or similar reference numerals represent the same or similar components. DETAILED DESCRIPTION

[0023] The technical scheme of the preferred embodiment of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection claimed in the present application.

[0024] like Figure 1 and Figure 2As shown, the embodiment of the present application provides a drawing die. In some embodiments, the drawing die can be one of a drawing die for the outer panel of a front cover of an automobile, a drawing die for the outer panel of a top cover of an automobile, a drawing die for the outer panel of a four-door outer panel of an automobile, and a drawing die for the lower outer panel of a trunk of an automobile. The drawing die shown in the drawings of the present application is a drawing die for the outer panel of a front cover of an automobile. The outer panel of the front cover of an automobile has a large area and is easy to generate a vacuum during the drawing process. The drawing die includes a concave die, a convex die 10, and a blank holder 20, wherein the concave die is not shown in the drawings of the present application. The concave die is concave to form a cavity for forming a blank, and the specific shape of the cavity can be determined based on the shape of the drawn product. The convex die 10 is formed with a protrusion 11, and the protrusion 11 can enter the cavity to cooperate with the cavity to draw the blank into a predetermined shape, and the specific shape of the protrusion 11 can also be determined based on the shape of the drawn product. In some embodiments, the blank can be plate-shaped, the convex die 10 can be the lower die of the drawing die, and the concave die can be the upper die of the drawing die. The blank holder 20 is arranged between the die and the punch 10. The blank holder 20 can cooperate with the die to press the blank to facilitate the drawing of the blank. The blank holder 20 can be a hollow ring structure in the middle. The raised portion 11 can pass through the middle of the blank holder 20 to press the blank into the cavity, so that it can cooperate with the cavity of the die to draw the blank into a predetermined shape. Exemplarily, the movement of at least one of the die, the punch 10 or the blank holder 20 can be driven by a hydraulic cylinder. In some embodiments, the punch 10 can remain stationary relative to the ground, and the hydraulic cylinder drives the die to move. The die and the blank holder 20 cooperate to press the blank, and then the die drives the blank holder 20 to continue to move toward the punch 10, so that the raised portion 11 of the punch 10 pushes the blank into the cavity; during the demolding process, the die moves away from the punch 10, and the die separates from the blank holder 20. The blank holder 20 also moves away from the punch 10 under the action of another driving force, driving the blank to separate from the raised portion 11 of the punch 10. When there is a vacuum between the blank and the raised portion 11, this process can easily cause deformation of the blank, causing quality defects.

[0025] like Figure 3 As shown, in this embodiment, a spring plunger 21 (Spring Plungers) is provided on the side of the blank holder 20 opposite to the die, and the spring plunger 21 has a spring top portion that protrudes from the blank holder 20 and can be elastically retracted. Figure 4As shown, the ejector pin 21 generally includes a cylindrical shell, a spring and an ejector top; the cylindrical shell is a hollow structure with an opening at one end, the spring is arranged in the hollow structure, the outer side of the cylindrical shell is provided with an external thread for cooperating with the internal thread to realize the installation and fixation of the ejector pin 21, the ejector top is telescopically arranged on the opening of the cylindrical shell, the opening edge of the cylindrical shell is radially concave inward to form a limiting edge for the ejector top, the limiting edge can limit the movement of the ejector top extending out of the cylindrical shell, the ejector top can be retracted into the cylindrical shell under the action of external force, and the spring is compressed at the same time, when the external force is removed or reduced, the ejector top extends out of the cylindrical shell under the action of the rebound force of the spring. In this embodiment, when the blank holder 20 cooperates with the die to press the blank, the blank acts on the spring top portion protruding from the blank holder 20, and the spring top portion is pressed back to the blank holder 20 by the blank; when the die is separated from the blank, the spring top portion can lift the blank from the blank holder 20, so that a gap for air to enter can be formed between the blank and the raised portion 11 during the demolding process, thereby eliminating the vacuum between the two and preventing the occurrence of blank deformation problems such as hollows and dark pits.

[0026] The drawing die provided by the embodiment of the present application is provided with a spring ejector pin 21 on the blank holder 20. During the demoulding process, the spring ejector pin 21 can lift the drawn blank for a distance, thereby eliminating the vacuum between the blank and the raised portion 11, avoiding the hollow pit caused by the vacuum and the pore oil pit caused by opening a hole at a low point on the main mold surface of the mold; and the spring ejector pin 21 can be installed by only opening a screw hole on the existing drawing die, so it is convenient for low-cost improvement of old equipment. The drawing die provided by the embodiment of the present application reduces production costs and rework rates, and improves production efficiency.

[0027] like Figure 2 As shown, in some embodiments, there are multiple ejector pins 21, and the multiple ejector pins 21 are distributed along the circumference of the blank holder 20. In this embodiment, by arranging multiple ejector pins 21 along the circumference of the blank holder 20, the blank can be lifted at multiple positions, making it easier to form a gap between the blank and the raised portion 11, thereby improving the effect of eliminating vacuum.

[0028] In some embodiments, the number of the ejector pins 21 is four, and the four ejector pins 21 are respectively arranged at the four corners of the blank holder 20. Preferably, a draw bead groove is provided on the blank holder 20, and the ejector pin 21 is arranged on one side of the draw bead groove away from the middle of the blank holder 20. More preferably, the ejector pin 21 is 60 to 100 mm away from the draw bead groove. The draw bead groove is a structure for the blank holder 20 to control the flow rate. In this embodiment, the above-mentioned position has a small inflow during the draw forming of the blank, which is conducive to the ejector pin 21 separating the blank from the blank holder 20 after the blank is formed.

[0029] In some embodiments, the concave die is the upper die of the drawing die, the convex die 10 is the lower die of the drawing die, and the sum of the spring forces of the multiple spring pins 21 is greater than the gravity of the blank. It can be understood that if the spring force of the spring pin 21 is too small, the elastic force is insufficient, and the spring pin 21 is difficult to lift the blank, and the spring pin 21 cannot function normally; if the spring force of the spring pin 21 is too large, it is easy to cause the blank to deform and the part size to deteriorate. In this embodiment, by reasonably setting the spring force of the spring pin 21, it can be ensured that the spring pin 21 can lift the blank. For example, taking the drawing die as a drawing die for the outer panel of the front cover of an automobile as an example, the weight of the blank of the outer panel of the front cover is 10.5kg, and the PJL16-20 (M16*85-20) model can be selected, and the light-loaded spring plunger telescopic ejector pin 21, the force of a single ejector pin 21 is 39.2N, and the ejector force of four ejector pins 21 is 32.9×4=156.8kgf, which is about 15.68kg. In some embodiments, the ejector force provided by the ejector pin 21 can exceed the weight of the blank by 20% to 30%, so that when the ejector pin 21 fails due to long-term fatigue, its ejector force can still meet the use requirements. In some embodiments, the ejector pin 21 is vertically arranged on the blank holder 20 to provide the maximum ejector force to the blank. In some embodiments, the top of the ejector pin is 13±2mm higher than the surface of the blank holder 20 to provide a better vacuum elimination effect.

[0030] In some embodiments, a screw hole is provided on the pressure ring 20, and the ejector pin 21 is arranged in the screw hole, and the depth of the screw hole is greater than the length of the cylindrical shell of the ejector pin 21. In this embodiment, this arrangement can ensure that the ejector pin 21 has sufficient installation adjustment margin in the screw hole. When the screw hole is provided on the pressure ring 20, the mold can be installed on a radial drilling machine to process the screw hole, and the bottom hole can be processed according to the thread and tooth shape of the ejector pin 21. When the PJL16-20 (M16*85-20) model ejector pin 21 is selected, a φ14 drill bit can be used to process the bottom hole, and an M16 coarse thread tap can be used for tapping. The depth of the screw hole can be 1.4 times the length of the cylindrical shell. When the ejector pin 21 is installed in the screw hole, an appropriate amount of thread locking agent can be added to the screw hole, and the cylindrical shell of the ejector pin 21 can be 3 to 5 mm lower than the base surface of the screw hole.

[0031] The drawing die provided by the embodiment of the present application makes up for the problem that the related technology cannot eliminate the vacuum problem in the pressing process of the shallow drawing die, and the oil pit defect problem caused by adding vent holes at the low points of the main profiles of the upper and lower dies; through the action force and reaction force, and the follow-up effect formed by demolding when the pressure ring rises during the pressing process of the die, the passive elimination of vacuum in the production and operation process of the die is changed to follow-up elimination; the drawing die provided by the embodiment of the present application has been effectively applied to eliminate the hollow pits of parts, eliminate the production stoppage rate of more than 95%, reduce the rework rate to 0.5%, and increase the production cycle to 11 times / minute; moreover, it is low in cost and simple to operate. The drawing die provided by the embodiment of the present application has low cost investment, will not damage the main profile of the drawing die substrate, and the effect is completely better than the drawing die with vent holes added at the low points of the main profiles of the upper and lower dies.

[0032] Based on the above-mentioned embodiments of the present application, in the absence of explicit negation or conflict, the technical features of one embodiment may be beneficially combined with one or more other embodiments.

[0033] Although some specific embodiments of the present application have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are only for illustration and not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A drawing die, characterized in that: include: A concave die, wherein the concave die is concave to form a cavity for molding the blank; A punch, wherein the punch is formed with a convex portion, and the convex portion can enter the cavity to cooperate with the cavity to draw the blank into a predetermined shape; A blank holder ring, the blank holder ring is arranged between the female die and the male die, the blank holder ring can cooperate with the female die to press the blank, and the raised portion can pass through the middle of the blank holder ring to press the blank into the cavity; Among them, a spring-loaded pin is arranged on the side of the blank holding ring opposite to the die, and the spring-loaded pin has a spring top portion protruding from the blank holding ring and being elastically retractable. When the blank holding ring cooperates with the die to press the blank, the spring top portion is pressed back to the blank holding ring by the blank. When the die is separated from the blank, the spring top portion can lift the blank from the blank holding ring, so that a gap for air to enter can be formed between the blank and the raised portion during the demolding process.

2. The drawing die according to claim 1, characterized in that: There are multiple ejector pins, and the multiple ejector pins are distributed along the circumference of the pressure ring.

3. The drawing die according to claim 2, characterized in that: The number of the ejector pins is four, and the four ejector pins are respectively arranged at the four corners of the pressure ring.

4. The drawing die according to claim 3, characterized in that: The blank holder ring is provided with a draw rib groove, and the ejector pin is arranged on one side of the draw rib groove away from the middle of the blank holder ring.

5. The drawing die according to claim 4, characterized in that: The ejector pin is 60 to 100 mm away from the drawbead groove.

6. The drawing die according to claim 2, characterized in that: The concave die is the upper die of the drawing die, the convex die is the lower die of the drawing die, and the sum of the ejection forces of the plurality of ejector pins is greater than the gravity of the blank.

7. The drawing die according to claim 1, characterized in that: The pressure ring is provided with a screw hole, the ejector pin is arranged in the screw hole, and the depth of the screw hole is greater than the length of the cylindrical shell of the ejector pin.

8. The drawing die according to claim 7, characterized in that: The ejector pin is vertically arranged on the pressure ring.

9. The drawing die according to claim 8, characterized in that: The top of the spring is 13±2 mm higher than the surface of the pressure ring.

10. The drawing die according to any one of claims 1 to 9, characterized in that: The drawing die is one of a drawing die for an automobile front cover outer panel, a drawing die for an automobile top cover outer panel, a drawing die for an automobile four-door outer panel, and a drawing die for an automobile trunk lower outer panel.

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