JP5285979B2 - Compact molding equipment - Google Patents

Description

  The present invention relates to a green compact molding apparatus, and more particularly to a mold apparatus that compresses and compacts a green compact of a substantially drum-shaped sintered part in an axial direction.

  In the case of manufacturing a precision cylindrical part such as a bearing, it is widespread to obtain a sintered part by heating and sintering a green compact obtained by compression molding raw material powder. The compacting of the green compact is obtained by filling the cavity formed in the die hole of the die with powder and compressing the powder in the axial direction by the upper and lower punches inserted into the die hole (see Patent Document 1, etc.). .

JP 2002-295475 A

  By the way, there is a demand for a sintered part having a drum shape with an outer peripheral surface having a cylindrical shape and a small-diameter constricted portion at an axially intermediate portion. In forming green compacts for such sintered parts, the constricted part becomes an undercut part and cannot be extracted from the die hole. A drum-shaped object can be obtained by a method such as processing. However, in such a method, the number of post-processes after sintering is increased and materials are wasted. Further, for these reasons, an increase in cost becomes a problem. Therefore, a technique capable of being manufactured only by the powder compression molding process has been desired. In addition, although the said patent document 1 describes the shaping | molding technique of the shape where the outer peripheral surface of an axial direction edge part becomes a small diameter, the technique about an axial direction intermediate part is a small diameter is not described.

  Therefore, according to the present invention, a cylindrical green compact having a constricted portion at the axially intermediate portion of the outer peripheral surface can be suitably compression-molded, and therefore, no post-process such as cutting after the sintered part is required In addition, an object of the present invention is to provide a mold apparatus in which waste of materials does not occur, and as a result, an increase in processes and costs can be suppressed and productivity can be improved.

The mold apparatus of the present invention is formed by compressing in the axial direction a green compact of a substantially drum-shaped sintered part having a cylindrical outer peripheral surface and a small-diameter constricted portion at an axially intermediate portion of the outer peripheral surface. A die apparatus, having a die hole that forms the shape of the outer peripheral surface of the green compact in a united state and capable of being divided in a direction perpendicular to the axial direction, and in a dividing direction via a slider on the punch holder And a plurality of divided dies provided so as to be movable , an urging means for urging the divided dies into a combined state, and arranged around the divided dies so as to be relatively movable in the axial direction with respect to the divided dies. An outer die, an upper punch and a lower punch, which are slidably inserted into the die hole of the split die in the combined state and compress the powder filled in the die hole in the axial direction, and the split die. , Splitting against the biasing force of the biasing means, E Bei and dividing means for enabling extracting the molded green compact from the divided dies in the axial direction, and the dividing means is a cam member provided in a state extending downward to the outer die, the outer die Is configured such that when the cam member is inserted between the sliders when the dies are moved downward relative to the split dies, a plurality of split dies are split .

  According to the present invention, powder is packed in a united split die, compression molded with upper and lower punches, and then the split die is split, whereby the compacted compact is extracted from the split die in the axial direction. be able to. By dividing the divided dies, the constricted portion of the inner peripheral surface of the die hole that has been engaged is separated from the formed constricted portion at the time of compression molding. The body can be extracted. For this reason, the green compact of the cylindrical part which has a constriction part in an outer peripheral surface can be shape | molded by one compacting process, and can be extracted after that.

In the present invention , the cam member has a wedge shape in which the left and right sides of the tip are formed in a tapered shape, and the tip of the cam member enters between the rollers mounted on the slider, thereby dividing a plurality of split dies. Includes form.

  According to the present invention, by dividing the divided die after compression molding the powder, a cylindrical green compact having a constricted portion at the axially intermediate portion of the outer peripheral surface can be extracted from the die in the axial direction. Therefore, the green compact of the cylindrical part can be suitably compression molded. This eliminates the need for post-processes such as cutting from sintered parts and eliminates waste of materials. As a result, it is possible to suppress an increase in processes and costs and improve productivity. Play.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[1] Sintered Part FIG. 1 shows a drum-shaped green compact obtained by compression molding in one embodiment. A hole 2 having a constant inner diameter is formed in the center of the green compact 1. On the other hand, the cylindrical outer diameter is not a constant outer diameter, the large-diameter portion 3 is formed at both axial end portions, and the constricted portion 4 having a smaller diameter than the large-diameter portion 3 is formed between the large-diameter portions 3. ing. The constricted portion 4 includes a bottom portion 4 a having a uniform diameter along the circumferential direction and a tapered portion 4 b extending from the bottom portion 4 a to the large diameter portion 3.

[2] Configuration of Mold Apparatus Next, a mold apparatus according to an embodiment for compressing and molding the green compact 1 shown in FIG. 1 from raw material powder will be described. FIG. 2 shows the mold apparatus. Reference numeral 10 denotes an outer die, and 11 denotes a yoke plate. The outer die 10 and the yoke plate 11 are connected by a plurality of guide rods 12. A punch holder 13 and a base plate 14 are slidably disposed on the guide rod 12 between the outer die 10 and the yoke plate 11 from above.

  At the center of the upper surface of the base plate 14, a cylindrical lower punch 15 extending vertically upward is fixed by a lower punch presser 16. A core rod insertion hole 17 is formed through the center of the lower punch 15. The core rod insertion hole 17 is formed such that a lower guide hole 17a and an upper slide hole 17b having a slightly smaller diameter than the guide hole 17a are continuous and concentrically formed.

  Fixed to the lower surface of the yoke plate 11 is a yoke plate 11 and a lower ram 18 that integrally moves the outer die 10 connected to the yoke plate 11 through a guide rod 12 up and down. A core rod 19 extending in the vertical direction is fixed to the center of the upper surface of the yoke plate 11 by a core rod presser 19a. The core rod 19 forms the hole 2 of the green compact 1, passes through the core rod through hole 14 a of the base plate 14, is inserted into the core rod insertion hole 17 of the lower punch 15 from the lower guide hole 17 a, and slides It penetrates in the state which slides in the hole 17b. The core rod 19 has a height (length) such that the upper end surface is flush with the upper surface of the outer die 10.

  On the upper surface of the punch holder 13, a split die 21 that is split in the left-right direction in the figure is provided. When the split dies 21 are combined, they become a cylindrical inner die 20. In other words, two split dies 21 are formed by vertically dividing the inner die 20 in the left-right symmetry.

  A large-diameter portion 22 is formed at the upper end in the axial direction and a flange portion 23 is formed at the lower end of the outer peripheral portion in a state where the divided dies 21 are combined to form the inner die 20. A small diameter portion 24 is formed between the flange portion 23 and the flange portion 23. In addition, a die hole 25 having a cylindrical inner peripheral surface is formed at the center of the inner die 20. A circumferential convex 26 that forms the constricted portion 4 is formed at the upper end in the axial direction of the die hole 25. A lower punch 15 penetrating a lower punch through hole 13a formed in the punch holder 13 is slidably inserted into the die hole 25 from below.

  A pair of left and right sliders 27 are provided on the upper surface of the punch holder 13 so as to be movable in the left-right direction. The flanges 23 of the divided dies 21 are respectively fixed on the sliders 27, and each divided die 21 can move in the left-right direction on the punch holder 13 together with the sliders 27. As shown in FIG. 3, tension springs (biasing means) 28 are stretched over the respective portions of the sliders 27 that are in contact with the divided dies 21, and the sliders 27 approach each other by the tension springs 28 (see FIG. 3). 3 (b) is urged in the direction of the arrow). Due to the urging force of the tension spring 28, the split dies 21 are usually configured such that the joining surfaces come into close contact with each other to form the inner die 20.

  Further, as shown in FIG. 3, a roller (guide) that rotates around the horizontal direction (vertical direction in FIG. 3A) perpendicular to the dividing direction on the outer side of the mounting portion of the tension spring 28 in each slider 27. Each member 29 is rotatably mounted. These rollers 29 are arranged in a state of projecting toward the mating slider 27 from the opposing ends of the sliders 27 that are separated or approaching. The two rollers 29 facing each other form a set, and the one set of rollers 29 are arranged in the moving direction of the slider 27 and are mounted at a predetermined interval.

  As shown in FIG. 2, the large-diameter portion 22 of the inner die 20 formed by combining the divided dies 21 is equal to the thickness of the outer die 10, and the large-diameter portion 22 is the inner die formed on the outer die 10. It is slidably fitted into the fitting hole 10a. As shown in FIG. 4, two cam bars (cam members) 31 projecting downward are fixed around the inner die fitting hole 10 a on the lower surface of the outer die 10. These cam bars 31 are arranged at locations corresponding to the central portion between the pair of rollers 29. The tip of the cam bar 31 has a wedge shape with the right and left side surfaces tapered.

  When the outer die 10 moves downward relative to the punch holder 13 and the inner die fitting hole 10a comes out of the large diameter portion 22 of the inner die 20, as shown in FIG. 31 enters between a pair of rollers 29 from above and descends while receiving the contact of both rollers 29. As a result, both rollers 29 are separated while rolling against the urging force of the tension spring 28, and the sliders 27 and the divided dies 21 are separated from each other following this. The outer die 10 descends around the small-diameter portion 24 of the inner die 20 so that a space for the split die 21 to move outward is formed between the inner peripheral surface of the inner die fitting hole 10a and the small-diameter portion 24. Therefore, the slider 27 Moves outward and the split dies 21 can be separated.

  When the main body, which is the portion above the tapered tip of the cam bar 31, is sandwiched between the rollers 29, the dividing die 21 is in the state of completion of separation with the furthest separation (see FIG. 5E). At this time, the space surrounded by the circumferential protrusions 26 of the separated divided dies 21 is larger than the outer diameter of the large-diameter portion 3 of the green compact 1, and the green compact 1 compression-molded in the inner die 20 is the shaft. It is possible to exit in the direction.

  An upper punch 35 that is slidably inserted into the die hole 25 from above is disposed above the inner die 20. The upper punch 35 is fixed to an upper punch plate 36 provided so as to move up and down with respect to the outer die 10 by an upper punch presser 37. An insertion hole 35 a for the core rod 19 is formed at the center of the upper punch 35.

[3] Molding of the green compact The above is the mold apparatus of one embodiment, and the procedure for molding the green compact 1 with the mold apparatus will be described with reference to FIG.
FIG. 5A is a process of filling the raw material powder, and the large-diameter portion 22 of the inner die 20 combined with the divided dies 21 is fitted in the inner die fitting hole 10 a of the outer die 10. The lower punch 15 is adjusted to a height position that forms the cavity C of the green compact 1 together with the die hole 25, and the cavity C is filled with powder from the powder feeder 40.

  Next, as shown in FIG. 5 (b), the upper punch 35 is lowered and inserted into the die hole 25, and the powder is compressed to form the green compact 1. When the green compact 1 is formed, the upper punch 35 is retracted upward and the outer die 10 is lowered as shown in FIG. As shown in FIGS. 5D to 5E, when the outer die 10 is further lowered, the cam bar 31 enters between the pair of left and right rollers 29, thereby separating the divided die 21 in the left-right direction. It will be divided. FIG. 5 (e) shows a state where the division is completed, and thereafter, as shown in FIG. 5 (f), the green compact 1 placed on the lower punch 15 as the punch holder 13 descends from the inside of the division die 21. It is extracted upwards.

[4] Effect of Embodiment According to the mold apparatus of the above embodiment, the cam bar 31 pushes the left and right rollers 29 apart by lowering the outer die 10 after compression molding of the green compact 1, and the slider 27. Is automatically performed in such a manner as to be separated in the left-right direction, and the dividing die 21 is divided. By dividing the dividing die 21 in this way, the green compact 1 can be extracted upward from the inside die 20. When the divided die 21 is divided, the circumferential convex shape 26 which is the constriction forming portion on the inner peripheral surface of the die hole 25 which is in close contact with the constricted portion 4 on the outer peripheral surface of the green compact 1 at the time of compression molding is formed. The green compact 1 can be extracted away from the constricted portion 4.

  For this reason, the operation of forming the green compact 1 having the constricted portion 4 on the outer peripheral surface in a single compacting process and then extracting it can be performed in a series of processes. As a result, post-processes such as cutting after sintered parts are not required, material is not wasted, and an increase in processes and costs can be suppressed, so that productivity can be improved.

[5] Modification of One Embodiment FIGS. 6 and 7 show a modification of the mold apparatus of the above-described embodiment. This mold apparatus is a withdrawal type in which the punch holder 13 is supported in a floating state, and the same reference numerals are given to the same components as those in the above-described embodiment. A plurality of cylinder devices 51 for supporting the punch holder 13 in a floating state are provided on the base plate 14 of the mold apparatus. The cylinder device 51 includes a cylinder 52 fixed on the base plate 14 and a piston 53 that extends and contracts upward from the cylinder 52. When the piston 53 extends upward, the piston 53 is moved to the punch holder 13. The punch holder 13 is supported in a floating state.

  Further, a pair of left and right pressure blocks with the lower punch 15 sandwiched between the lower portion of the punch holder 13 and the central portion in the depth direction in FIG. 6 (the position corresponding to the central portion in the vertical direction in FIG. 7C). 55 is fixed. On the other hand, slide blocks 56 that receive the pressure blocks 55 are provided at positions corresponding to the pressure blocks 55 on the base plate 14 so as to be movable in the left-right direction. As shown in FIG. 7C, a slit 56a is formed at the end of each slide block 56 on the outer side in the left-right direction, and in the slit 56a, the roller 29 and the roller 57 whose rotation axis is parallel. Is rotatably mounted. Further, a cam bar 58 extending downward is fixed to a position corresponding to each roller 57 on the lower surface of the outer die 10. The front ends of these cam bars 58 are formed in a wedge shape with the outer side in the left-right direction cut into a tapered surface.

  The slide blocks 56 are normally urged toward each other by a spring or the like (not shown). In this state, when the floating support state of the punch holder 13 by the cylinder device 51 is released, the punch holder 13 is lowered. The pressure block 55 is placed on the slide block 56. When the outer die 10 is lowered from this state, the tip tapered surface of the cam bar 58 comes into contact with the roller 57. When the outer die 10 is further lowered, the roller 57 and the slide block 56 are pushed outward by the cam bar 58 and moved. The cam bar 58 enters the slit 56a, and at that time, the slide block 56 is disengaged from the pressure block 55, so that the punch holder 13 is lowered until the pressure block 55 falls on the base plate 14. Yes.

  FIG. 8 shows a process of powder compression molding by the mold apparatus shown in FIGS. In this mold apparatus, first, as shown in FIG. 8A, the punch holder 13 is supported in a floating state by the cylinder apparatus 51, and the cavity C in the inner die 20 is filled with powder. Next, the powder is compression-molded by the upper and lower punches 35 and 15 while the floating support state by the cylinder device 51 is maintained. At this time, the inner die 20 supported by the punch holder 13 is urged upward by the cylinder device 51, whereby the powder can be compressed while balancing the urging force and the compressive force. (FIG. 8B).

  When the powder is compressed to form the green compact 1, the floating support state of the cylinder device 51 is released, and the pressure block 55 is placed on the slide block 56. Next, as shown in FIGS. 8C to 8E, the outer die 10 is lowered to separate the split die 21, and the inner die 20 is split. At the stage of FIG. 8 (e), the inner die 20 is in a state of completion of division, and the outer die 10 is further lowered from here. Then, the cam rod 58 pushes the roller 57 and the slide block 56 outward, the slide block 56 comes out of the pressure block 55, and the pressure block 55 falls on the base plate 14 until the pressure holder 55 falls to the base plate 14. The die 21 is lowered. Then, the green compact 1 placed on the core rod 19 is extracted upward from the split die 21.

  Also according to this modification, the drum-shaped green compact 1 having the constricted portion 4 can be compression-molded once so that it can be extracted from the die, as in the above-described embodiment. The cylinder device 51 that supports the punch holder 13 in a floating state is effective in that the upward biasing force can be adjusted, but the load from the punch holder 13 is elastically simply in the floating state. 9, the punch holder 13 may be supported by a coil spring 61 instead of the cylinder device 51 as shown in FIG.

It is (a) top view and (b) side view of the drum-shaped green compact compressed and molded with the metal mold apparatus concerning one embodiment of the present invention. It is sectional drawing of the metal mold | die apparatus which concerns on one Embodiment of this invention. (A) The top view which shows each component on a punch holder of the metal mold | die apparatus, (b) The front view. (A) The top view of the outside die of the metallic mold device, (b) The front view. It is sectional drawing which shows the process in which powder is compression-molded with the metal mold | die apparatus of one Embodiment in order of (a)-(f). It is sectional drawing of the modification which added the cylinder apparatus which floats and supports a punch holder to the metal mold | die apparatus of one Embodiment. (A) The top view of an outside die of the metallic mold device of a modification, (b) The top view showing each component on a punch holder, (c) The top view of a base plate. It is sectional drawing which shows the process of compression-molding powder with the metal mold | die apparatus of a modification in order of (a)-(f). It is sectional drawing of the metal mold | die apparatus of the modification which replaced the floating support apparatus with the spring.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Green compact 4 ... Constriction part 10 ... Outer die 15 ... Lower punch 20 ... Inner die 21 ... Divided die 25 ... Die hole 28 ... Tension spring (biasing means)
29 ... Roller (guide member)
31 ... Cam rod (cam member)
35 ... Upper punch C ... Cavity

Claims (2)

A mold apparatus for compressing and molding green compacts of substantially drum-shaped sintered parts having a cylindrical outer peripheral surface and a small diameter constricted portion at an axially intermediate portion of the outer peripheral surface,
It has a die hole that forms the shape of the outer peripheral surface of the green compact in the combined state, can be divided in a direction perpendicular to the axial direction, and is provided on the punch holder so as to be movable in the dividing direction via a slider. With multiple split dies,
An urging means for urging the divided dies into a combined state;
An outer die disposed around the split die so as to be movable relative to the split die in the axial direction;
An upper punch and a lower punch, which are slidably inserted into the die holes of the split dies in the combined state and compress the powder filled in the die holes in the axial direction;
The split die, by divided against the biasing force of the biasing means, e Bei and dividing means for enabling withdrawal axially compacted powder compact from the divided dies,
The dividing means is a cam member provided in a state extending downward in the outer die,
The compacting powder according to claim 1 , wherein when the outer die moves relative to the divided die downward, the cam member enters between the sliders to divide a plurality of divided dies. Body molding die equipment. The cam member has a wedge shape in which the left and right sides of the tip are tapered, and a plurality of split dies are divided by the cam member tip entering between rollers mounted on the slider. The green compact molding apparatus according to claim 1.

Images