JP2019166537A - Forging metal mold - Google Patents

Abstract

To provide a metal mold which hardly varies the position of a split die even when a die height or temperature varies and thereby keeps a high precision and a long lifetime of a molded article.SOLUTION: A metal mold 1 consists of: a bottom force 10, comprising a die case 11, a counter punch 13 at the center of the same, a plurality of split dice 12 arranged to be movable radially, and a resetting elastic body 14; and a top force 20, comprising a punch case 21, a punch 22 which clamps a material 2 by cooperation with the counter punch 13, and a cam 23 which presses the cam face 12 of the split dice 12 to move the split dice inward, has a backup face 11 where the die case 11 faces a pressure-receiving face 12e at the rear end of the split dice 12, and a block 24 keeping the top force 20 inserted between the pressure-receiving face 12e and the backup face 11.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a mold, and more particularly, to a cold forging mold for manufacturing a product having a spherical shape or a barrel shape and having a groove in a spherical shape portion, such as an inner ring of a constant velocity joint.

  The parts used for the inner ring of the constant velocity joint used for the front wheel shaft and drive shaft connecting part of the FF vehicle have a spherical outer shape, and a ball groove extending in the vertical direction is formed on the surface thereof. . When such a part is forged and formed, it is manufactured with an upper and lower divided mold, but due to the upper and lower divisions, upper and lower mold parting lines are formed in the ball grooves. Therefore, there is a limit to the molding accuracy of the groove.

  Further, in the case of an inner ring for a Lebro joint having a ball groove that is inclined with respect to the central axis, since there is an inclined ball groove, it cannot be formed by closed forging of the vertical division type. In order to solve this problem, Patent Document 1 discloses a manufacturing method and a manufacturing apparatus in which radially divided split dies are reciprocated in the radial direction by a cam mechanism. However, in this apparatus, a cam surface having a tapered surface is used to move the divided die, and the load acting on the divided die during molding is received by the tapered surface.

JP 2000-140984 A

  In the apparatus of Patent Document 1, since the load at the time of molding is received on the tapered surface of the divided dies, the surface roughness of the tapered surfaces is managed, the contact surface between the tapered surfaces is secured, and the dimensional variation between the divided dies is managed. Therefore, high part processing accuracy is required. Further, since the radial position of the divided dies is determined via the tapered surface, an error in the radial direction is caused by an error in the height direction. Therefore, the position of the taper surface changes due to the influence of the die height adjustment of the press machine and the change of the die height due to the temperature rise of the mold during press and press machine, and the radial position of the split dies also changes. To do. As a result, the accuracy of the product is lowered and the life of the split die is shortened.

  The present invention eliminates such problems of the conventional mold, and the position of the split die is not easily changed even under the influence of the adjustment of the die height of the press machine or the temperature change. An object of the present invention is to provide a mold for molding a molded product having a spherical portion with a long die life.

  The mold 1 of the present invention is arranged in a die case 11, a counter punch 13 that is arranged to be movable up and down at the center of the die case, and is arranged so as to be movable in the radial direction so as to surround the counter punch. A lower die having a plurality of divided dies 12 having a cam surface 12f formed of a surface and having a machining surface 15 formed at the inner end, and an urging member (elastic body 14) for urging the divided dies outward. 10; a punch case 21; a punch 22 disposed in the center of the punch case to clamp the material 24 in cooperation with the counter punch 13; and a cam 23 that presses the cam surface 12f to move inward. The upper mold 20 is provided. The die case 11 has a backup surface 11f that is perpendicular to the moving direction of the divided die 12 and faces inward, and the divided die 12 has a pressure receiving surface 12e that is perpendicular to the moving direction and faces outward, The upper die 20 includes a block 24 that is inserted between the pressure receiving surface 12e and the backup surface 11f after the division die 12 is moved, and transmits an outward load received by the division die 12 to the backup surface 11f. Yes.

  In such a mold 1, the divided die 12 has a pressure receiving surface 12 e on the outer end surface, and includes protrusions 12 c on the left and right side surfaces, and the cam surface 12 f is formed on these protrusions. Is preferred. In addition, the distance between the pressure receiving surface 12e and the backup surface 11f when the cam 23 moves the split die 12 inward in the radial direction is slightly narrower than the corresponding dimension of the block 24, thereby the split die. After the movement of 12, the block 24 is preferably configured to be positioned by moving the dividing die 12 slightly inward in the radial direction when the block 24 is inserted between the pressure receiving surface 12e and the backup surface 11f. The upper cam 23 may also serve as the block 24.

  In the mold of the present invention, the split die is provided with a cam surface for moving in the radial direction and a pressure receiving surface for receiving the molding load, and the positioning after the movement of the split die and the pressure received during molding are the same as the cam surface. It is performed on the pressure receiving surface perpendicular to the separate moving direction. Thus, in the mold of the present invention, the moving mechanism of the split die and the positioning pressure receiving mechanism are separated, and the pressure receiving surface is perpendicular to the moving direction, so that adjustment of the die height of the press machine, The structure is less susceptible to changes in height and errors, such as changes in die height due to temperature rise in the press machine. As a result, the part machining accuracy of the tapered surface is relaxed, and the influence of the die height of the press machine can be eliminated.

  When the split die has a pressure receiving surface on the outer end surface, and has protrusions on the left and right side surfaces, and the cam surface is formed on these protrusions, the reaction force received by the split die during pressure processing is received. You can communicate straight to the backup surface by the surface and block. Therefore, the bending deformation of the split dies is small, and the processing accuracy is increased. Moreover, since the pressure receiving surface is provided on the outer end surface of the split die, it can be designed to be large. Therefore, the surface pressure received by the pressure receiving surface of the divided dies, the backup surface of the die case, and the corresponding surface of the block in contact with them can be reduced, and durability is increased. Although the cam surface of the split die is shifted in the lateral direction to the left and right with respect to the processing surface, the main action of the cam surface is the movement of the split die and is not subjected to pressure during processing. Therefore, even if the cam surface is flat with respect to the processed surface, it does not cause bending or the like.

  The distance between the pressure receiving surface and the backup surface when the split die is moved radially inward is slightly narrower than the corresponding dimension of the block, so that after the split die is moved, the block is separated from the pressure receiving surface. When it is configured to position the splitting die slightly inward in the radial direction when inserted between the backup surfaces, the operation of moving the splitting die to the center side is performed in two steps by a cam and a block. Done in Therefore, the positioning of the divided dies is performed with higher accuracy.

  When the upper cam also serves as a block, the number of parts can be reduced.

It is a perspective view which shows one Embodiment of the metal mold | die of this invention. 2A is a bottom view of the upper mold, and FIG. 2B is a plan view of the lower mold. It is a longitudinal cross-sectional view of the metal mold | die of FIG. 1, and has shown only the right side from the center. It is a perspective view of the division | segmentation die used for the metal mold | die of FIG. FIG. 2B is an enlarged plan view showing the tip of the split die of FIG. 2B. 6A to 6D are process diagrams showing a molding process using the mold shown in FIG. 7A to 7C are process diagrams showing a molding process subsequent to FIG. 6D. 8A, 8B, and 8C are a plan view, a side view, and a perspective view showing an example of a molded product molded with the mold of the present invention.

  A mold 1 shown in FIG. 1 is a forging die by a press machine composed of a lower die 10 and an upper die 20, particularly a cold forging die. When molding, the lower mold 10 is fixed to a bolster of a press machine, and the upper mold 20 is fixed to a slide. FIG. 1 shows when the slide is at top dead center. The mold 1 forms a molded product 3 (an intermediate product of an inner ring of a constant velocity joint) shown in FIGS. 8A to 8C from a cylindrical material (reference numeral 2 in FIG. 3).

  The lower die 10 is a cylindrical die case 11, a plurality of divided dies 12 which are accommodated in a guide groove 11 a formed on the upper surface of the die case 11, and are provided so as to be movable in the radial direction, and the die case 11. The counter punch 13 is arranged at the center of the dies so as to be movable up and down, and an elastic body such as a compression coil spring that urges the divided dies 12 outward (biasing member, reference numeral 14 in FIG. 3). In this embodiment, the number of divided dies 12 is six, which matches the number of ball grooves (reference numeral 31 in FIG. 8A) of the inner ring of the constant velocity joint to be manufactured.

  As shown in FIGS. 1 and 3, a step portion 11 b that fits the upper mold 20 protrudes from the outer peripheral edge of the upper surface of the die case 11. The guide groove 11 a has a depth corresponding to the height of the divided die 12, and the upper surface of the divided die 12 accommodated in the guide groove 11 a is flush with the upper surface of the die case 11. As shown in FIG. 2B, the planar shape of the guide groove 11a is substantially the same as the outer shape of the split die 12, and further, a gap 11c that allows the split die 12 to move in the radial direction is formed.

  As shown in FIG. 3, an accommodation groove 11d for accommodating the elastic body 14 and a deep groove 11e for accommodating a pressure receiving portion 12b of the divided die 12 described later so as to be movable in the radial direction are formed on the bottom surface of the guide groove 11a. Yes. The outer surface of the accommodation groove 11d is a backup surface 11f facing inward. Further, a hole 11g is formed in the bottom surface of the housing groove 11d or the deep groove 11e to allow a tip of a cam 23 described later to escape.

  The counter punch 13 has a cylindrical shape and is accommodated in a through hole 11h formed in the center of the die case 11 so as to be movable up and down. The lower end of the counter punch 13 is attached to a knockout device of a press machine, and the counter punch 13 rises to take out the molded product 3 after processing (see FIG. 7C).

  As shown in FIG. 4, the split die 12 includes a prismatic center portion 12a, a plate-shaped pressure receiving portion 12b provided at a rear end of the center portion at a right angle to the center portion, and a side surface of the center portion 12a. Projecting portion 12c projecting left and right. Their upper surfaces are flush with each other, and the lower surface of the protrusion 12c is flush with the lower surface of the central portion 12a. The pressure receiving portion 12b is wider than the central portion 12a, and the lower end protrudes downward from the central portion. The protruding portion is a receiving portion 12 d that engages with the end portion of the elastic body 14. The rear surface of the pressure receiving portion 12b is a pressure receiving surface 12e perpendicular to the moving direction of the split die 12.

  The projecting portion 12c is a thin prismatic shape, and a cam surface 12f made of an inclined surface rising inward is formed at the upper end of the rear portion. The reason why the area of the cam surface 12f is smaller than that of the conventional cam type is that the cam surface 12f is only used for the movement of the split die 12 and is not substantially involved in molding. By providing a pair of left and right projections 12c, the pressure receiving portion 12b can be provided at the rear end of the center portion 12a, and the pressure applied during molding can be smoothly transmitted to the pressure receiving surface 12e.

  A rear surface 12g (surface extending downward from the lower end of the cam surface 12f) 12g is perpendicular to the moving direction (radial direction) of the split die 12, and a vertical surface of the cam 23 of the upper mold 20 described later comes into contact therewith. The surface that slides. Furthermore, in this embodiment, a slight tapered surface 12h is formed at the corner at the rear of the upper end of the pressure receiving portion 12b. The tapered surface 12h guides easily when the lower end of the block 24, which will be described later, is fitted between the pressure receiving portion 12b and the backup surface 11f. There is a function of converting the pressure into a horizontal force that presses the dividing die 12 toward the center. Furthermore, in this embodiment, a small tapered surface 24 a is also provided on the front side of the lower end of the block 24.

  The tip of the central portion 12a of the split die 12 is a processing surface 15 for forming the material into a predetermined shape. In this embodiment, as shown in FIGS. 4 and 5, a spherical concave surface 15a for forming a spherical surface (reference numeral 30 in FIG. 8A) of the molded product 3 and a ball groove (FIG. 8A is formed with an arcuate ridge 15b having a circular cross section and a forward end positioning portion 15c formed obliquely from the front surface to the side surface of the left and right ends. The advancing end positioning portion 15c is a portion where the adjacent divided dies 12 abut against each other at the time of molding, thereby enclosing the material without a gap and restricting the divided dies 12 from entering the center side any more. .

  The upper mold 20 includes a cylindrical punch case 21 and a punch 22 that is fixed to the center of the punch case 21 and protrudes downward. Further, a vertically extending cam 23 and a block 24 are fixed at positions corresponding to the divided dies 12 so as to surround the punch 22 as a center, and project from the lower surface of the punch case 21. The cam 23 moves the split die 12 toward the center, and an inclined surface 23a is formed at the front corner of the lower end so as to be in sliding contact with the cam surface 12f of the split die 12. As shown in FIG. 2A, two pairs of cams 23 are provided symmetrically with respect to a line indicating the radius. The block 24 positions the split dies 12 and is arranged at right angles to a line indicating the radius. As described above, a small tapered surface 24 a is formed on the front surface side of the lower end of the block 24.

  In the upper mold 20, a disc-shaped presser plate 25 is disposed below the punch case 21 so as to be movable in the vertical direction, and the presser plate 25 is interposed in the punch case via cushion pins 26 extending vertically. It is urged downward by a hydraulic cylinder 27 in 21. The cushion pins 26 are pistons 26a whose upper ends slide in the hydraulic cylinder 27, and a plurality of cushion pins 26 are arranged at equal intervals with respect to the center of the punch case 21 (see FIG. 2A). A through hole 25 a through which the material 2 and the tip of the punch 22 pass is formed at the center of the presser plate 25. Further, the presser plate 25 is formed with through holes 25b and 25c through which the cam 23 and the block 24 pass.

  The presser plate 25 functions to hold the divided die 12 during molding and to remove a molded product that has bite into the punch 22 after molding. In addition, when the block 24 inserted between the pressure receiving surface 12e of the divided die 12 and the backup surface 11f of the die case 10 is extracted, it also functions to hold the divided die 12 so as not to follow. The presser plate 25 can be held vertically movable by fixing the lower end of the cushion pin 26 to the presser plate 25 and suspending the presser plate 25 by the cushion pin 26. However, it is also possible to provide another member for supporting the presser plate 25 so as to be movable up and down with respect to the punch case 21 and restricting the descending end.

  FIG. 3 is simplified, and a seal structure of the hydraulic cylinder 27 and a cover member mounting structure for closing the upper end of the hydraulic cylinder 27 are omitted. Further, a punch plate or a punch holder which is attached to the upper surface of the punch case 21 to back up the upper ends of the punch 22, the cam 23 and the block 24 and which is fixed to the slide of the press machine is not shown. Similarly, a die holder attached to the lower surface of the die case 11 is not shown.

  Next, with reference to FIGS. 6 and 7, a process of forming the material 2 into the molded product 3 using the above-described mold 1 will be described. 6 and 7, only the right half of the mold 1 is shown as in FIG. 3, and the left half is omitted. The lower die 10 is fixed to a bolster of a press machine, and the upper die 20 is fixed to a slide. In FIG. 6A, the split die 12 is urged outwardly and expanded by the elastic member 14, and the pressure receiving portion 12b is in contact with the left and right surfaces (reference numeral 11i in FIG. 2B) of the deep groove 11e. In this state, the cylindrical material 2 is placed on the counter punch 13 and the operation of the press machine is started.

  When the slide is lowered and the upper die 20 is lowered as shown in FIG. 6B, first, the presser plate 25 comes into contact with the upper surface of the split die 12, and the upper portion of the gap between the material 2 and the processing surface 15 of the split die 12 is closed. A space S having a height of is formed. The lower end of the lower surface of the presser plate 25 is regulated by the upper surface of the die case 11. At this time, the upper portion of the material 2 enters the through hole 25a at the center of the presser plate 25. When the slide is further lowered, as shown in FIG. 6C, the inclined surface 23a of the cam 23 comes into contact with the cam surface 12f of the split die 12 and pushes the split die 12 toward the center. The dividing die 12 is guided by the guide groove 11a and moves to the center side while compressing the elastic body 14.

  As shown in FIG. 6D, when the contact between the inclined surfaces 23a of the cam 23 and the cam surface 12f of the divided die 12 is finished and the vertical surfaces are in contact with each other and slide, the movement of the divided die 12 is performed. Has ended. At this time, the position of the dividing die 12 is approximately in front of the regular position by a minute amount of 1 mm or less (see reference symbol L in FIG. 5). On the other hand, at this time, the small tapered surface 24 a provided at the tip of the block 24 comes into contact with the tapered surface 12 h at the upper end of the pressure receiving surface 12 e of the split die 12.

  Thereafter, the upper die 20 is lowered as shown in FIG. 7A, and the divided dies 12 are advanced by a minute amount L by the action of the small tapered surface 24a and the upper tapered surface 12h. It will become a regular position by contacting (refer the imaginary line of FIG. 5). In this case, the forward movement of the divided die 12 is restricted by the abutting of the advancing end positioning portions 15c, and the play or clearance is made zero by the abutting pressure. Further, since there is no gap between the adjacent divided dies 12, there is almost no parting line on the surface of the material.

  At the same time when the divided die 12 comes to the normal position, the block 24 fits between the pressure receiving surface 12e of the divided die 12 and the backup surface 11f of the die case 11. When the molding load pushes the split die 12 outward, the outward pressure is transmitted from the pressure receiving surface 12e of the split die 12 to the backup surface 11f via the block 24 and is supported by the die case 11. As a result, the position of the split die 12 is accurately maintained. At that time, the punch 22 comes into contact with the material 2 and molding starts. The tip position of the split die 12 in FIGS. 6D and 7A is shown in FIG. A solid line is the state of FIG. 6D and an imaginary line is the state of FIG. 7A. 7A, the tip of the cam 23 is inserted into the hole 11g of the die case.

  FIG. 7B shows a state where the press machine is at the bottom dead center and the molding is finished. The columnar material 2 is sandwiched between the punch 22 and the counter punch 13, and the middle part expands, and plastically flows so as to fill the space formed by the processing surface 15 at the tip of the divided die 12. A molded product 3 having a spherical shape is obtained. Since the molding at this time is a molding in a so-called hydrostatic pressure state in which the periphery is constrained and the whole is compressed, the fluidity of the material is increased, and high-precision processing is possible.

  Thereafter, the slide rises, the block 24 and the cam 23 are detached from the lower mold 10 by the reverse operation to the above, and the divided die 12 returns to the initial position by the recovery of the elastic body 14. Thereafter, the counter punch 13 is raised, and the molding is completed by taking out the molded product 3 and raising the upper die 20 to the top dead center.

  As mentioned above, although preferable embodiment was described, this invention is not limited to these, A various deformation | transformation can be employ | adopted. For example, in FIG. 3, the hydraulic cylinder 27 is employed as means for applying a downward urging force to the presser plate 25 because a long stroke and a stable pressure can be obtained, but an air cylinder may be used. Further, depending on the stroke length, a coil spring, rubber or the like can be employed.

1 Mold 2 Material 3 Molded product 10 Lower mold 11 Die case 11a Guide groove 11b Stepped portion 11c Clearance 11d Housing groove 11e Deep groove 11f Backup surface 11g Hole 11h Through hole 11i Right and left surfaces 12 of the deep groove Split die 12a Center portion 12b Pressure receiving portion 12c Protruding part 12d Receiving part (spring receiving)
12e Pressure receiving surface 12f Cam surface 12g Rear surface 12h of projection part Tapered surface (pressure receiving part)
13 Counter punch 14 Elastic body (spring)
15 Processing surface 15a Spherical concave surface 15b Convex strip 15c Advance end positioning portion 20 Upper die 21 Punch case 22 Punch 23 Cam 23a Inclined surface 24 Block 24a Small taper surface (block)
25 Presser plates 25a, 25b, 25c Through hole S Space L Small amount 26 Cushion pin 26a Piston 27 Hydraulic cylinder 30 Spherical surface 31 Ball groove

Claims (4)

An inner end having a die case, a counter punch that can be moved up and down in the center of the die case, and a cam surface that is radially movable so as to surround the counter punch and that has a high inclined surface inside. A lower mold comprising a plurality of divided dies having a processed surface formed thereon, and an urging member that urges the divided dies outward.
A punch case, and a punch that is arranged in the center of the punch case and clamps the material in cooperation with the counter punch, and an upper mold that includes a cam that presses and moves the cam surface inward.
The die case has a back-up surface perpendicular to the moving direction of the divided dies and facing inward;
The split dies have a pressure-receiving surface perpendicular to the moving direction and facing outward;
A mold having a block in which the upper die is inserted between the pressure receiving surface and the backup surface after the split die is moved, and transmits an outward load received by the split die to the backup surface.   The mold according to claim 1, wherein the split die has a pressure receiving surface on an outer end surface, and includes protrusions on left and right side surfaces, and the cam surface is formed on the protrusions. The distance between the pressure receiving surface and the backup surface when the split die is moved radially inward is slightly narrower than the corresponding dimension of the block,
3. After the movement of the split dies, the split dies are moved slightly inward in the radial direction when the block is inserted between the pressure-receiving surface and the backup surface. The mold described.   The mold according to claim 1, wherein the upper mold cam also serves as a block.

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