JP2012218015A - Die opening prevention structure of press die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of die opening at the time of press forming by a die opening prevention structure which is simple and low cost and does not increase the number of steps in die manufacture, relating to a press die.SOLUTION: In a press die M, a guide hole 25 is opened in the length direction of central part of an upper die body 15 of an upper die M2, a work presser 20 is energized at all times toward a lower die formation surface P by a gas spring 35, in the guide hole, for vertical sliding in lifting direction. Meanwhile, a knock hole 45 is formed which includes a first hole 45a penetrating a support plate and a second hole 45b of the same aperture which communicates with the first hole opened on the upper die body, at a position where the support plate overlaps with the upper die body on both sides across the guide hole when the support plate 40, assembled with the gas spring, is put on the upper side of the guide hole, to be secured to the upper die body. A knock pin 50 whose aperture r is identical with a shaft diameter s, otherwise an interference is within a dimension tolerance at interference fit, is press-fitted in the knock hole, so that the support plate is tightly connected to the upper die body with no gap.

Description

  The present invention comprises a fixed-side lower mold on which a plate-shaped workpiece is placed and set, and a movable-side upper mold that moves up and down with respect to the lower mold and press-molds the workpiece. The present invention relates to a mold opening prevention structure for preventing an upper mold from opening on both sides of a work clamp during press molding in a press mold that is slidable in a direction.

  Conventionally, this type of press mold is used for bending a frame of an automobile, for example, and as shown in FIG. 5 (A), on the lower mold forming surface 1b provided on the lower mold body 1a, For example, it is composed of a fixed lower mold 1 on which a plate-shaped workpiece w having a thickness of 1.6 mm is placed and set, and a movable upper mold 2 that moves up and down relative to the lower mold 1 to press-mold the workpiece w. The mold 2 is provided with a guide hole 4 for the work retainer 3 along the length direction at the center of the upper mold body 2a. The work retainer 3 is inserted into the guide hole 4 by a plurality of gas springs 5 and the lower mold forming surface 1b. The support plate 6 with the gas spring 5 assembled is placed on the upper side of the guide hole 4 and fixed to the upper mold body 2a with bolts 7 while being urged constantly toward the upper and lower directions in the figure. The work plate 3 is supported by the support plate 6 via the gas spring 5. There. During press molding, the workpiece w is placed on the lower mold molding surface 1b and set, and then the upper mold 2 is lowered with respect to the lower mold 1, and the web surface of the workpiece w is molded with the workpiece presser 3 and the lower mold molding. While pressing against the surface 1b, the upper die 2 is further lowered against the biasing force of the gas spring 5, and the flange portion is pushed by the die 2b and the punch 1c to bend the workpiece w into a hat shape. ing.

  However, in this conventional press die, the support plate 6 assembled with the gas spring 5 is fixed to the upper die body 2a with the bolts 7 above the guide holes 4, but the upper die 2 is the central portion of the upper die body 2a. Is a cavity with a guide hole 4 opened in the lengthwise direction, and as shown in FIG. 5B, a screw on the upper mold body 2a side into which the screw portion 7a of the bolt 7 is screwed into the bolt hole 8 Since the clearance hole 8c through which the shaft portion 7b of the bolt 7 is inserted is formed in the support plate 6 between the hole 8a and the counterbore 8b and the gap d is opened, the upper die 2 is formed during press molding. Is lowered with respect to the lower mold 1, and the work w is pushed in and clamped, the mold parts on both sides sandwiching the guide hole 4 of the upper mold body 2 a are, for example, one side as shown by the chain line in FIG. As a result, the mold is clamped between the die 2b of the upper die 2 and the punch 1c of the lower die 1. Workpiece w is deformed by the reaction force upon the quality of the product is lowered.

  Therefore, in the conventional press die, as shown in FIGS. 6 and 7, a reinforcing rib 9 that crosses the guide hole 4 is installed on the upper die 2, and the guide hole 4 is sandwiched between the upper die body 2a. However, there is a structure in which the main body 2a of the upper mold 2 is prevented from opening to the outside of the guide hole 4 during press molding by connecting the mold parts on both sides with reinforcing ribs 9 to reinforce the integrity. .

Japanese Patent Laid-Open No. 11-268095 JP 2002-219528 A

  However, in the conventional press die opening prevention structure described above, the reinforcing rib 9 is installed across the guide hole 4 in the upper mold 2 while the work retainer 3 is divided into two parts with the reinforcing rib 9 as a boundary. Therefore, in the work retainer 3, the contact surface that requires lubricating oil in the guide hole 4 is increased to 8 surfaces, and the distance between the two work retainers 3 and 3 is increased. It is also necessary to connect using the connecting member 3a. As a result, the structure is complicated, the number of parts is increased, the product cost is increased, and the number of manufacturing processes is increased, which requires time and labor for the mold production. It was.

  Accordingly, an object of the present invention is to prevent mold opening from occurring during press molding by a simple and inexpensive mold opening prevention structure that does not increase the man-hours for mold production in the press mold as described above. is there.

  Therefore, in order to solve the above-described problem, the invention described in claim 1 is a plate-like workpiece W on the lower mold forming surface P provided in the lower mold main body 11, for example, as shown in the following illustrated embodiment. A fixed lower mold M1 and a movable upper mold M2 that moves up and down with respect to the lower mold M1 and press-molds the workpiece W. The upper mold M2 is composed of an upper mold body 15. A guide hole 25 is formed in the central portion length direction, and the work presser 20 is constantly urged toward the lower mold forming surface P by the gas spring 35 of the urging means in the guide hole 25 so as to be slidable vertically. On the other hand, in the press mold M in which the support plate 40 assembled with the urging means is put on the upper side of the guide hole 25 and fixed to the upper mold body 15, the upper mold M2 is the upper mold body 15 When the support plate 40 is fixed to the front, the support plate 40 The first hole 45a penetrating the support plate 40 and the first hole 45a drilled in the upper mold body 15 are communicated with the upper mold body 15 on both sides of the guide hole 25 therebetween. A knock hole 45 consisting of a second hole 45b having a hole diameter is formed, and a knock pin 50 having the same diameter or an interference fit as the hole diameter r and the shaft diameter s is press-fitted into the knock hole 45 and the above-mentioned knock pin 50 having a dimensional tolerance range is press-fitted. The support plate 40 is tightly coupled to the upper mold main body 15 without a gap.

  According to the first aspect of the present invention, the upper mold has the same diameter as that of the knock hole formed at the position where the support plate overlaps the upper mold main body on both sides of the guide hole sandwiched between them. Since the structure has a structure in which a dowel pin with a large dimensional tolerance range is press-fitted and the support plate is tightly connected to the upper die body without gaps, when the workpiece is clamped between the lower die and the lower die during press molding, Even if the mold parts on both sides of the guide hole of the main body try to open outward, the shear force acting on the upper mold main body side and the shearing force acting on the support plate side at that time are controlled by the knock pin to restrict the mold opening As a result, a necessary and sufficient press load is applied to the workpiece, and as a result, the workpiece can be pressed without being deformed, thereby preventing the quality of the product from deteriorating. Can do. Moreover, because the work clamp is designed to prevent the workpiece from being opened in the guide hole of the upper mold without dividing the work clamp as in the past, it is possible to increase the contact surface required for lubricating oil in the work clamp, and to separate the workpiece. Since it is a simple structure in which it is not necessary to connect between the pressers with a connecting member, it is possible to prevent the mold opening at the time of press molding at a low cost without increasing the number of parts and man-hours for mold production.

(A) is a schematic longitudinal cross-sectional view which shows the press die which applied the mold opening prevention structure which is an example of this invention in a press state, (B) is a partial expanded schematic sectional view which expands and shows the principal part of this invention. is there. It is a schematic longitudinal cross-sectional view which shows the same press metal mold | die in the state before an upper mold | type descend | falls with respect to a lower mold | type. It is a schematic plan view which shows an upper mold | type. It is a schematic longitudinal cross-sectional view which shows the process of bending a workpiece | work with a press metal mold | die divided into three steps of (A) * (B) * (C). (A) is a schematic longitudinal cross-sectional view which shows the conventional press metal mold | die in a press state, (B) is a partially expanded schematic cross-sectional view which expands and shows the bolting position of the conventional press metal mold | die. It is a schematic plan view which shows the upper mold | type of the conventional press metal mold | die provided with the mold opening prevention structure. It is a schematic longitudinal cross-sectional view which shows the press metal mold | die.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  1 to 4 show a press die to which a mold opening preventing structure as an example of the present invention is applied. The press mold M in the illustrated example includes a fixed-side lower mold M1 and a movable-side upper mold M2 that moves up and down relative to the lower mold M1 to press-mold the workpiece W.

  The lower mold M1 is formed by fixing the lower mold body 11 on the base 10, as shown in FIG. On the lower die body 11, a punch 12 having a convex shape is fixed in accordance with the shape of the product to be bent of the workpiece W, and a lower die forming surface P on which the workpiece W is set on the upper surface of the punch 12 is formed. To do.

  The upper mold M2 is hung downward by fixing the upper mold main body 15 to an elevating member 14 that is vertically moved up and down by an elevating drive device (not shown). The upper mold main body 15 is made of cast iron, and as shown in FIG. 3, a long and narrow guide hole 25 is provided in the longitudinal direction of the center portion so as to match the work presser 20 in the up and down direction in FIG. A symmetric die 30 is fixed below the guide hole 25 so as to face each other with the guide hole 25 interposed therebetween. The upper die body 15 is disposed in the guide hole 25 so as to be slidable in the up and down direction in a state where the work presser 20 is urged toward the lower die forming surface P by the gas springs 35 of a plurality of urging means. To do. The work presser 20 has a plurality of insertion holes 21 in accordance with the gas springs 35. The gas springs 35 are erected in a row on an elongated rectangular steel support plate 40. Accordingly, the support plate 40 is formed by inserting the gas springs 35 into the insertion holes 21 of the work presser 20 and covering the upper side of the guide holes 25 with the work presser 20 being always pushed down by the urging force of the gas springs 35. The mold body 15 is fixed with bolts 39. At that time, the bolt 39 is screwed into a plurality of bolt holes 41 screwed to the upper mold body 15 on which the support plate 40 overlaps on both sides of the guide hole 25 interposed therebetween.

  By the way, when the support plate 40 is fixed to the upper mold body 15, the upper mold M <b> 2 according to the present invention is arranged in the middle in the longitudinal direction on both sides with the guide holes 25 interposed therebetween as shown in FIG. 3. A pair of knock holes 45 having a hole diameter r of 16 mm, for example, are formed at symmetrical positions overlapping the mold body 15. As shown in FIG. 1B, the knock hole 45 is a second hole having the same hole diameter r communicating with the first hole 45a penetrating the support plate 40 and the first hole 45a formed in the upper die body 15. It consists of a hole 45b. Therefore, the upper die 15 press-fits the support plate 40 by press-fitting a steel knock pin 50 in which the hole diameter r and the shaft diameter s are the same or an interference fit is within a dimensional tolerance range (for example, 0.02 mm). The upper mold body 15 is tightly coupled with no gap.

  Now, when the workpiece W is bent using the illustrated press mold M having the above-described configuration, and a product, for example, an automobile frame is processed into a hat mold, as shown in FIG. After the work W is placed on the surface P and set, the lift driving device is actuated to lower the upper mold M2 with respect to the lower mold M1, and as shown in FIG. The upper die M2 is further lowered against the urging force of the gas spring 35 while the workpiece is held between the work retainer 20 and the lower die forming surface P, and as shown in FIG. 30 and the punch 12 of the lower mold | type M1 push in a flange part, and the workpiece | work W is bend-shaped by a hat type | mold.

  Therefore, according to the illustrated press die M, the upper die M2 is a knock formed at a position where the support plate 40 overlaps the upper die main body 15 at approximately the middle in the longitudinal direction on both sides with the guide hole 25 interposed therebetween. A knock pin 50 having the same hole diameter r and shaft diameter s or having a large dimensional tolerance range is press-fitted into the hole 45 so that the support plate 40 is tightly coupled to the upper mold body 15 without any gaps. When the workpiece W is clamped between the lower mold M1 and the mold parts on both sides of the upper mold body 15 with the guide holes 25 sandwiched between them as shown by the chain line in FIG. As shown in FIG. 5B, the mold pin is restricted from receiving the shearing force X acting on the upper die body 15 side and the shearing force Y acting on the support plate 40 side by the knock pin 50 at that time. As a result, a necessary and sufficient press load is applied to the workpiece W, and the result , It is possible to press working without deforming the workpiece W, it or more, the quality of the product can be prevented from being lowered.

  In addition, the illustrated press die M has a mold opening prevention structure in which the work presser 20 is not divided as in the prior art and is disposed in the guide hole 25 of the upper mold M2, so that the work presser 20 needs a contact surface that requires lubricating oil. In addition, since it is a simple structure that does not require connection between the divided work clamps with a connecting member, it can be used at low cost without increasing the number of parts and man-hours for mold production. Mold opening can be prevented.

  In the illustrated example described above, the urging means for urging the work presser 20 is the gas spring 35. However, the urging means is not limited to the gas spring, and for example, other than a spring member such as a coil spring or a leaf spring. An elastic member having an appropriate elastic force is also included.

M Press mold M1 Lower mold M2 Upper mold P Lower mold surface r Knock hole diameter s Knock pin shaft diameter 11 Lower mold body 12 Punch 15 Upper mold body 20 Work clamp 25 Guide hole 30 Die 35 Gas spring means)
40 support plate 45 knock hole 45a first hole 45b second hole 50 knock pin

Claims (1)

A fixed-side lower mold on which a plate-shaped workpiece is placed and set on a lower mold forming surface provided in the lower mold main body, and a movable-side upper mold that moves up and down relative to the lower mold and press-molds the workpiece The upper mold has a guide hole in the central portion length direction of the upper mold main body, and a work presser is constantly urged toward the lower mold forming surface by an urging means in the guide hole and slides up and down in the vertical direction. On the other hand, in a press mold for fixing the support plate assembled with the biasing means on the upper side of the guide hole and fixing it to the upper mold body,
When the support plate is fixed to the upper mold body, the upper mold has a first hole penetrating the support plate at a position where the support plate overlaps the upper mold body on both sides of the guide hole. And forming a knock hole comprising a second hole having the same hole diameter communicating with the first hole formed in the upper die body, and the hole diameter and the shaft diameter are the same or tightened with an interference fit. A press-opening prevention structure for a press die, wherein a knock pin having a dimensional tolerance range is press-fitted and the support plate is tightly connected to the upper die body without a gap.

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