JP5580680B2 - Molding equipment for closed forging - Google Patents

Description

  The present invention relates to a mold apparatus for closed forging, which is one of plastic processing, and more particularly to a closed mold forging apparatus that enables high-precision forging under a relatively simple mold structure. is there.

  A closed forging die device for the purpose of forging a connecting rod for an internal combustion engine has been proposed in Patent Document 1.

  In the thing of this patent document 1, the lower die | dye which will form the sealed space for a forged product is divided | segmented into four division | segmentation dies of front, back, left, and right as a die piece, and those division dies are While being accommodated in a die case having a substantially rectangular frame shape, each divided die and the die case are in contact with each other with an inclined cam surface. Then, when the split die and the die case are moved relative to each other in the vertical direction, each split die advances from the front, rear, left, and right directions to close the lower die and form a sealed space. As a result, the workpiece (coarse material) Is forged into a predetermined forged product shape.

JP-A-4-197546

  However, in the technique described in Patent Document 1, since the workpiece is formed into a predetermined shape only after the four divided dies that are independent from each other are closed, it is difficult to align the four divided dies. There is a limit to improving the dimensional accuracy of workpieces that are forged products.

  In addition, combined with the difficulty in positioning the four split dies as described above, each die is engraved so that the target shape can be obtained accurately when the four split dies are combined. Similarly, there is a limit to improving the dimensional accuracy of a work that is a forged product.

  The present invention has been made paying attention to such problems, and is capable of performing high-precision forging under a relatively simple mold structure, and for closed forging to improve the dimensional accuracy of a workpiece. A mold apparatus is provided.

  The mold device for closed forging according to the present invention has a pair of movable molds having an inclined cam surface on the back side and capable of approaching and separating from each other, and an inclined cam surface in sliding contact with the above-described pair of movable mold side inclined cam surfaces And a die case for moving the pair of movable molds toward and away from each other by moving relative to the pair of movable molds.

Then, the above pair of movable mold are formed respectively between the pair of inner mold relatively movable in the approaching separation direction of the movable die between the outer mold, tilting to both of these inner mold and outer mold cam When the pair of movable molds move closer together with the relative movement between the pair of movable molds and the die case, the pair of movable outer molds are first attached to each other. A sealed space for the workpiece is formed, and then forging is performed by moving the inner molds closer to each other so as to reduce the sealed space.

  According to the present invention, since molding by closed forging is performed based on the approaching and separating operation of a pair of movable molds formed by an inner mold and an outer mold that can move relative to each other, a large number of conventional movable molds This eliminates the difficulty of alignment and die-sculpting, enables high-precision forging, and improves and stabilizes the dimensional accuracy of the workpiece.

Cross-sectional explanatory drawing which shows the general | schematic basic structure of the die apparatus for closed forging which concerns on this invention. FIG. 2 is an exploded perspective view of a pair of movable molds that are main elements of the mold apparatus of FIG. 1. FIG. 2 is an operation explanatory view of the mold apparatus of FIG. 1, and is a cross-sectional view showing a state in which a pair of movable molds are raised from the state of FIG. 1. FIG. 4 is an operation explanatory view of the mold apparatus of FIG. 1, and is a cross-sectional view showing a state in which a pair of movable molds are lowered from the state of FIG. 3. Sectional drawing of the metal mold apparatus which actualized the basic structure of FIG. 1 more. The disassembled perspective view of one movable type | mold which is a main element of the metal mold | die apparatus of FIG. FIG. 6 is an operation explanatory view of the mold apparatus of FIG. 5, and is a cross-sectional view showing a state in which a pair of movable molds are lowered from the state of the figure. FIG. 8 is an operation explanatory view of the mold apparatus of FIG. 5, and is a cross-sectional view showing a state where the pair of movable molds are further lowered than the state of FIG. 7. Schematic explanatory drawing which shows a pair of movable type modification.

  FIGS. 1-8 is a figure which shows embodiment of the metal mold | die apparatus for closed forging which concerns on this invention, The example of the metal mold | die apparatus for forging the connecting rod for internal combustion engines is shown here.

  1 and 2 show a schematic basic structure of the above-mentioned closed forging die device, in which a rectangular cylindrical die case 2 is fixed on a bolster 1, and a pair is placed in the die case 2 on the left and right. A pair of movable molds 3 and 4 are accommodated in a state of facing each other. Of the four inner peripheral surfaces of the die case 2, two surfaces facing each other are inclined cam surfaces 5 and 6. That is, the inclined cam surfaces 5 and 6 where the facing distance between the two surfaces gradually decreases downward. On the other hand, inclined cam surfaces 11 and 12 having the same inclination corresponding to the inclined cam surfaces 5 and 6 on the die case 2 side are also formed on the back side of the pair of movable dies 3 and 4. As will be described later, when the pair of movable molds 3 and 4 are integrally moved up and down with respect to the die case 2, the pair of movable molds 3 and 4 move toward and away from each other according to the lifting and lowering operation. It will be.

  As shown in FIG. 2, the pair of movable molds 3 and 4 is formed by incorporating an inner mold 9 or 10 having a substantially similar shape inside an outer mold 7 or 8 having a substantially rectangular parallelepiped shape. The mold 7 or 8 and the inner mold 9 or 10 can be moved relative to each other, and can be moved relative to each other in a direction perpendicular to the ascending / descending direction of the pair of movable molds 3 and 4 itself, that is, in the horizontal direction. As described above, the inclined cam surfaces 11 and 12 are formed on the back surfaces of the inner dies 9 and 10 and the outer dies 7 and 8, while the front surfaces of the inner dies 9 and 10 correspond to the finished shape of the forged product. Opening portions 15 and 16 for receiving or fitting the impression portions 13 and 14 on the inner mold 9 and 10 side are formed on the front surfaces of the outer molds 7 and 8, respectively. Yes. As described above, when the outer mold 7 and the inner mold 9 or the outer mold 8 and the inner mold 10 move relative to each other in the horizontal direction, the inner molds are opened from the openings 15 and 16 on the outer mold 7 and 8 side. The impression parts 13 and 14 on the mold 9 and 10 side appear and disappear.

  Each of the inner dies 9 and 10 has a stepped portion 17 that is one step lower than the impression portions 131 and 4, and each of the outer dies 7 and 8 has a convex shoulder portion 18. , 8 is restricted by the contact between the step portion 17 and the shoulder portion 18.

  As can be seen from FIGS. 1 and 2, the inclined cam surfaces 11 and 12 of the inner molds 9 and 10 are formed with convex portions 19 having a cross-sectionally inverted trapezoidal shape, while the die case 2 side is inclined. The cam surfaces 5 and 6 are formed with dovetail grooves 20 that engage with the projections 19, and both of them have dovetail guide surface structures as an uneven fitting guide surface structure. Accordingly, the inner molds 9 and 10 have a structure that does not fall off the inclined cam surfaces 5 and 6 of the die case 2. The dovetail guide surface structure described above is merely an example, and in other words, if the function of preventing the inner molds 9 and 10 from coming off from the inclined cam surfaces 5 and 6 of the die case 2 can be exhibited, other types of uneven fitting guide surfaces are provided. It is also possible to adopt a structure.

  Therefore, according to the closed forging die device configured in this way, as shown in FIG. 3, in a state where the pair of movable dies 3 and 4 are raised with respect to the die case 2, both movable dies A workpiece (coarse material) W is introduced into the gap between the three and four, and the pair of movable dies 3 and 4 are lowered from the top dead center position to the bottom dead center position by a slide or the like (not shown). In this state, as shown in FIG. 3, it is assumed that the inner dies 9 and 10 are in a position where the inner dies 9 and 10 are retracted with respect to the outer dies 7 and 8 of the movable dies 3 and 4. In addition, the workpiece W is loaded with the portion to be the large end on the upper side and the portion to be the small end on the lower side.

  The pair of movable dies 3 and 4 are integrally lowered along the inclined cam surfaces 5 and 6 on the die case 2 side, and at the same time, the movable dies 3 and 4 move toward each other toward the workpiece W. Become.

  When the pair of movable molds 3 and 4 are further lowered, the movable molds 3 and 4 are simultaneously approached at the same time, so that as shown in FIG. 8 will contact | abut. In this state, a closed space R for closed forging is formed for the first time by both outer molds 7 and 8 and inner molds 9 and 10.

  Thereafter, the inner molds 9 and 10 move forward relative to the outer molds 7 and 8 of the movable molds 3 and 4 while maintaining the sealed space R, and the volume of the sealed space R is gradually reduced. Finally, until the pair of movable molds 3 and 4 reach the bottom dead center position, that is, the shoulders 18 on the inner molds 9 and 10 side contact the shoulders 18 on the outer molds 7 and 8 side. Both inner molds 9 and 10 move forward until they come into contact. As a result, the workpiece W is pressed and restrained by both the inner dies 9 and 10 and the outer dies 7 and 8 in the sealed space R, and finished into a predetermined forged product shape.

  Thus, when the pair of movable molds 3 and 4 reach the bottom dead center position, when the pair of movable molds 3 and 4 are pushed up by knockout or the like (not shown) instead, the pair of movable molds 3 and the workpiece W after forging are formed. , 4 will return to the state of FIG.

  5 to 8 show the structure of a closed forging die device that further embodies the above basic structure, and the same reference numerals are given to the parts common to FIGS.

  5 to 8, return springs 22 as elastic bodies are respectively interposed between the outer mold 7 and the inner mold 9 and between the outer mold 8 and the inner mold 10 of the movable molds 3 and 4. And, in that the holder plate 25 for controlling the retraction limit position of the inner dies 9 and 10 with respect to the outer dies 7 and 8 is attached, it differs from that shown in FIGS. Yes. However, in FIGS. 5 to 8, the work W to be put into the sealed space R is not shown.

  As shown in FIG. 6 in addition to FIG. 5, a plurality of spring seats 21 that are opposed to each other are recessed in the inner bottom surfaces of the outer dies 7, 8 and the step portions 17 of the inner dies 9, 10. 2 (see FIG. 2 for the spring seats 21 on the inner dies 9 and 10 side), and between the spring seats 21 and 21 facing each other, a compression coil spring type return spring 22 is interposed as an elastic body. It is. As a result, the inner molds 9 and 10 guided by the outer molds 7 and 8 are always urged in the retreating direction. Note that the compression coil spring type return spring 22 is merely an example, and it is of course possible to use, for example, a rubber spring such as urethane, a disc spring, or a gas cushion as an elastic body.

  Further, as shown in FIG. 6, a concave groove 23 is formed in each of the inner molds 7, 8 facing the inner mold 7, while the outer mold 7 is formed on the outer mold 7, 10. , 8 are formed to match the groove 23 on the 8 side. Then, a holder plate 25 is mounted with a bolt or the like (not shown) on the bottom of the concave groove 23 on the outer mold 7 or 8 side, and a part of the holder plate 25 is engaged with the concave groove 24 on the inner mold 9 or 10 side. It is. As a result, as described above, even if the inner molds 9 and 10 guided by the outer molds 7 and 8 are always urged by the return spring 22 in the retreating direction, the holder plate Thus, the position restriction of the retreat limit position of the inner dies 9 and 10 with respect to the outer dies 7 and 8 and the retaining are performed.

  Therefore, according to the mold structure shown in FIG. 5, when the pair of movable molds 3 and 4 are pushed down by the slide 26, the pair of movable molds 3 and 4 are formed in the die case as in the case of FIGS. The pair of movable molds 3 and 4 move toward each other while descending along the two inclined cam surfaces 5 and 6. In this case, each of the inner dies 9, 9 receives the driving force in the approaching direction by sliding contact between the inclined cam surfaces 5, 6 on the die case 2 side and the inclined cam surfaces 11, 12 on the movable mold 3, 4 side. Even if only 10 is provided, a return spring 22 is interposed between the inner molds 9 and 10 and the outer molds 7 and 8, so if the inner molds 9 and 10 approach each other, the return spring 22 is interposed. Thus, both outer molds 7 and 8 also move closer to each other. Thereby, each operation | movement reliability of the inner mold | types 9 and 10 and the outer mold | types 7 and 8 becomes a high thing.

  Then, when the outer molds 7 and 8 of both the movable molds 3 and 4 come into contact with each other while the slide 26 and the pair of movable molds 3 and 4 are descending, as shown in FIG. R will be formed. At this time, the inclined cam surfaces 11 and 12 on the inner molds 9 and 10 side are merely in sliding contact with the inclined cam surfaces 5 and 6 on the die case 2 side, and the inclined cam surfaces on the outer molds 7 and 8 side. The surfaces 11 and 12 are not in contact with the inclined cam surfaces 5 and 6 on the die case 2 side.

  When the slide 26 and the pair of movable molds 3 and 4 are lowered, as shown in FIG. 8, the inner molds 9 and 10 of both movable molds 3 and 4 are moved closer to each other to reduce the volume of the sealed space R. Finally, when the slide 26 and the pair of movable molds 3 and 4 reach the bottom dead center, that is, not only the inclined cam surfaces 11 and 12 on the inner mold 9 and 10 side in both movable molds 3 and 4. The inclined cam surfaces 11 and 12 on the outer molds 7 and 8 side are in sliding contact with the inclined cam surfaces 5 and 6 on the die case 2 side, and the inner molds with respect to the shoulder portions 18 on the outer molds 7 and 8 side. Forging is completed when the stepped portions 17 on the 9th and 10th sides are in contact with each other.

  In this way, not only the inclined cam surfaces 11 and 12 on the inner molds 9 and 10 side in both movable molds 3 and 4 but also the inclined cam surfaces 11 and 12 on the outer molds 7 and 8 side are inclined on the die case 2 side. By being driven in sliding contact with the cam surfaces 5 and 6, the workpiece W can be pressed and restrained with a greater force.

  Thereafter, when the pair of movable molds 3 and 4 are pushed up by the knockout 27 together with the raising operation of the slide 26, both the movable molds 3 and 4 return to the state shown in FIG. 5 together with the workpiece W after forging. . In this case, since the inclined cam surfaces 5 and 6 on the die case 2 side and the inclined cam surfaces 11 and 12 on the inner molds 9 and 10 side have a groove guide surface structure as described above, By simply pushing up the pair of movable molds 3 and 4 with the knockout 27, the inner molds 9 and 10 are separated from each other, and the inner molds 9 and 10 and the outer molds 7 and 4 in the process of the pair of movable molds 3 and 4 rising. 8 is regulated by the holder plate 25, so that not only the separating operation between the inner molds 9 and 10 but also the separating operation between the outer molds 7 and 8 is performed stably, and its operation reliability is high. It will be a thing.

  As described above, according to the present embodiment, the molding is performed by closed forging based on the approaching and separating operation of the pair of movable molds 3 and 4 formed by the inner molds 9 and 10 and the outer molds 7 and 8 that are relatively movable. Therefore, the difficulty in positioning and engraving a large number of movable molds as in the prior art is eliminated. As a result, high-precision forging can be performed, and the dimensional accuracy of the workpiece W, which is a forged product, can be improved and stabilized.

  Here, in the above embodiment, the inclination degrees of the inclined cam surfaces 11 and 12 on the outer mold 7 and 8 side and the inner mold 9 and 10 side are the same, but depending on the shape of the workpiece W, etc. In order to positively control the operation timing and the approaching / separating speed of the molds 7 and 8 and the inner molds 9 and 10, the inclined cam surfaces 11 and 12 on the outer molds 7 and 8 side and the inner molds 9 and 10 side respectively. It is also possible to make the inclinations different from each other.

  For example, as shown in FIG. 9, the inclination angle of the inclined cam surfaces 11a, 12a on the inner mold 7, 8 side is set larger than the inclination angle of the inclined cam surfaces 11b, 12b on the outer mold 7, 8 side with respect to the vertical surface. To do. Of course, the inclined cam surfaces 5 and 6 on the die case 2 side are also in sliding contact with the inclined cam surfaces 11a and 12a on the inner mold 9 and 10 side and the portions that are in sliding contact with the inclined cam surfaces 11b and 12b on the outer mold 7 and 8 side. Needless to say, it is necessary to make the inclination angles different from each other. In this case, the approach / separation operation speed between the inner dies 9 and 10 can be made relatively larger than that of the previous embodiment, and can be applied to closed forging of workpieces of various shapes, High versatility.

2 ... Die case 3, 4 ... Movable type 5, 6 ... Inclined cam surface 7, 8 ... Outer die 9, 10 ... Inner die 11, 12 ... Inclined cam surface 17 ... Stepped portion 18 ... Shoulder portion 19 ... Convex portion 20 ... Dovetail groove 22 ... Return spring (elastic body)
R ... sealed space W ... work

Claims (4)

A pair of movable molds having an inclined cam surface on the back side and capable of approaching and separating from each other;
A die case that has an inclined cam surface that is in sliding contact with the pair of movable mold-side inclined cam surfaces and moves the pair of movable molds toward and away from each other by moving relative to the pair of movable molds;
With
The pair of movable molds are formed respectively as an inner mold and an outer mold that are relatively movable in the approaching and separating directions of the pair of movable molds, and inclined cam surfaces are provided on both the inner mold and the outer mold. Each formed ,
When the pair of movable molds approach each other as the pair of movable molds and the die case move relative to each other, the pair of movable molds are first brought together to form a sealed space for the workpiece. Then, forging is performed by moving the inner molds close to each other so as to reduce the sealed space.   2. The closed forging die device according to claim 1, wherein the pair of movable molds and the die case can be moved toward and away from each other and can be relatively moved in the orthogonal direction. Between the inner mold and the outer mold forming each movable mold, an elastic body for biasing in a direction in which both movable mold outer molds approach each other is interposed. Item 3. A mold apparatus for closed forging according to item 1 or 2. Said die case and the each of the inner mold, closed forging die apparatus according to claim 3, characterized in that the retaining by recess-projection fitting guide surface structures in the inclined cam surfaces of the both are facilities.

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