JP2969330B2 - Powder press equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder press apparatus for compacting a stepped circular part having a step on the outer periphery of a cylindrical surface whose center line extends vertically. Things. 2. Description of the Related Art Generally, when manufacturing powder sintered parts or the like, it is necessary to first compress powder into a predetermined shape by a powder pressing device. In the case of a circular component, the outer peripheral surface is formed by a cylindrical die, and the upper and lower end surfaces are formed by the compression operation of the upper and lower punches. In the case of a shape having a portion, in the structure of a powder press apparatus generally used in the past, there is a fear that seizure may occur in a part of the punch due to repeated press forming. [0003] That is, in the case of a circular part having steps having different diameters on the outer periphery of a cylindrical surface, in order to make the compression density in each part of the molded product uniform, a lower punch is provided corresponding to each step. Is divided into a cylindrical shape, and with the downward compression operation of the upper punch, the outer portion of the lower punch moves according to its length,
The ratio between the height at which the powder is filled before compression and the height of the product after compression is made uniform at each step (for example, see Japanese Utility Model Laid-Open No. 55-13973). However, in the case of the flange-shaped step portion, when the step thickness is small, that is, when the amount of projection in the diameter direction due to the change in diameter is small, the thickness of the punch member in this portion is also small, and the rigidity is low, and the pressing process The punch member acts to spread the punch member outward and deforms, and the outer peripheral portion relatively slides on the inner peripheral surface of the outer die in a strong pressure contact state. Due to the repetition of the press forming, a sliding streak occurs in the longitudinal direction on the contact surface between the two, and finally there is a possibility that seizure may occur. [0005] Further, as another molding apparatus for a stepped circular part, for example, as disclosed in Japanese Utility Model Laid-Open No. 127327/1985, an outer die has a shape corresponding to a flange-shaped step of a circular part. There is a method in which a stepped die having a notch is formed and a movable upper punch is pressed against a fixed lower punch to perform press molding. However, with the stepped die and the fixed lower punch as described above, the problem of the seizure of the lower punch as described above is reduced, but the compression density at each part of the molded product is reduced. It is difficult to make it uniform. That is, the compression operation is performed only from the upper punch, and the internal pressure rise is different between the flange portion and the main body portion in relation to the movement of the die, and the powder moves inside and finally becomes uniform as a whole. It is difficult to obtain a compressed density. SUMMARY OF THE INVENTION In view of the above circumstances, the present invention improves the rigidity of the lower punch, reduces deformation due to press pressure, prevents the occurrence of seizure in the punch, and improves the performance of each part. And to provide a powder press apparatus capable of obtaining a uniform compressed density. [0008] The powder pressing apparatus of the present invention, which has solved the above-mentioned problems, has an outermost step in a stepped circular part having a step on the outer periphery of a cylindrical surface whose center line extends vertically. The outer peripheral surface of the portion, the bottom surface of the outermost step, and a molding surface corresponding to the shape of the outer surface following the lower part of the outermost step, the outer punch plate movable up and down from the lower end by an outer punch plate An outer lower punch supported, having a molding surface corresponding to the shape of the bottom surface other than the above, including an inner lower punch supported by an inner punch plate, wherein the outer lower punch and the inner lower punch are relatively movable. To form a lower punch, on the outside of the outer lower punch, a ring-shaped guide plate that guides the outer peripheral surface of the lower punch so as to be able to move up and down is provided.
An upper punch having a forming surface corresponding to the shape of the upper surface of the component from the upper side is disposed so as to be axially movable with respect to the lower punch. According to the present invention as described above, the outer lower punch has a large thickness, has high rigidity, reduces deformation due to press pressure, and can move up and down outside the outer lower punch. By providing a suitable guide plate and supporting the lower end with an outer punch plate that can move up and down, it can properly carry various loads during molding and prevent the occurrence of sliding seizure on its outer peripheral surface, Good compaction can be performed over a long period of time. Also, by receiving the outer lower punch and the inner lower punch with separate plates and performing press forming while relatively moving both, the outer lower punch is also formed with a stepped portion,
Since the internal pressure difference is small, the flow of the powder is suppressed and the final compressed density can be made uniform. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded cross-sectional view of a main part of a powder pressing apparatus in a pressed state of a circular part. The stepped circular component 1 to be compacted has a flange portion 1b (outermost step) protruding from the upper outer periphery of an outer peripheral surface 1a as a cylindrical surface whose center line extends vertically.
A through hole 1c is formed at the center, the upper end surface 1d is substantially flat, and the lower end surface 1e has a projection 1f protruding in the axial direction on the center side. The part 1 is formed by pressing a lower punch 4 composed of an inner lower punch 2 and an outer lower punch 3 for forming the bottom surface and the peripheral surface of the part 1 and pressing the upper part from the lower part forming surface 5a. An upper punch 5 for forming the upper end surface 1d of the component 1 and a core rod 6 for forming a central through hole 1c on the outer peripheral surface. The inner lower punch 2 has a fixed lower punch 7 having an upper end forming surface 7a for forming the bottom surface of the bottom protrusion 1f of the component 1, and an inner peripheral surface and a lower end surface 1e for forming the peripheral surface of the protrusion 1f. And an inner lower punch 8 having each forming surface 8a at the upper end surface to be formed. The outer lower punch 3 has a molding surface 3a for molding the outer peripheral surface 1a of the component 1 and the bottom surface and the peripheral surface of the flange portion 1b. That is, the molding surface 3a
Is formed by an inner peripheral forming surface corresponding to the outer peripheral surface 1a of the component 1 and a notch 9 forming a concave forming surface corresponding to the bottom surface and the peripheral surface of the flange portion 1b. The core rod 6, the fixed lower punch 7, the inner lower punch 8, and the outer lower punch 3 are arranged concentrically in order from the inside to the outside. The core rod 6, the inner lower punch 8 And an outer lower punch 3 are provided to be slidable up and down in the axial direction, respectively. That is, the outer lower punch 3 and the inner lower punch 2 are relatively movable. Outside the outer lower punch 3, a ring-shaped guide plate 10 for supporting the outer peripheral surface is slidably disposed. FIG. 2 shows a supporting structure of the above-mentioned punches 2 to 4, and FIG. 2 shows a powder filling state before pressing. The fixed lower punch 7 of the inner lower punch 2 has a pipe-shaped lower end supported by a cylindrical fixed base 13 via a first plate 12 (inner punch plate) and held in a fixed state. The core rod 6 penetrating through the inside of the fixed lower punch 7 is connected to and supported by the core 14 in the fixed base 13 through the first plate 12, and is slid when the component 1 is ejected. On the other hand, the lower ends of the inner lower punch 8 and the outer lower punch 3 have a second plate 15
(An inner punch plate) and a third plate 16 (an outer punch plate) via a bottom platen 17 and a standard platen 18. Further, the guide plate 10 is further supported by a top platen 19 on the outer periphery. Further, the upper punch 5 has an upper end connected and supported by a press mechanism 20. The bottom platen 17 and the standard platen 18 are configured such that the lowering position at the time of pressing is restricted by a press stop (not shown), and the press stop releases the restriction after pressing and shifts to an eject operation. Have been. The bottom platen 17 and the standard platen 18 are provided with lifting cylinders (not shown), respectively, and are moved up and down to predetermined positions. In addition, the bottom platen 17 and the standard platen 18 are urged upward at the time of pressing to respond to the pressing operation of the upper punch 5. It moves downward. Further, in order to supply the powder P, a powder feeding shoe 21 which is slidable in a lateral direction in contact with the upper surface of the top platen 19 is provided. The operation of the above configuration will be described. First, when the powder P is supplied for compacting, as shown in FIG. 2, the core rod 6, the inner lower punch 8, the outer lower punch 3, and the guide plate 10 (top platen 19) are moved to the raised position. Then, the tip of the core rod 6, the upper end surface of the outer lower punch 3 and the upper end surface of the guide plate 10 (top platen 19) are flush with each other. The space P to be formed is filled with the powder P. At this time, the shape of the space portion is set so as to be enlarged in the vertical direction so that a predetermined compression ratio can be obtained in each portion with respect to the product size of the component 1. Next, the upper punch 5 is moved down by the pressing force of the press mechanism 20, and the lower end molding surface 5a is brought into contact with the upper surface of the powder P, and is further lowered to start press molding. With the lowering of the upper punch 5, the outer lower punch 3 and the inner lower punch 8 are lowered to a position corresponding to the product shape and stopped by a press stop (not shown), and the upper punch 5 is also moved to a predetermined position corresponding to the product shape. Then, the powder P is compressed to the size of the part 1 as shown in FIG. Subsequently, the operation shifts to an eject operation, in which the press stop of the outer lower punch 3 and the inner lower punch 8 is released and further lowered by a cylinder (not shown). Thereby, as shown in FIG. 3, the outer lower punch 3 and the inner lower punch 8 are pulled out from the peripheral surface of the component 1 and the core rod 6 is pulled out from the inner surface of the component, and the upper end of the inner lower punch 8, the outer lower punch 3 and the core rod 6 are pulled out. The height is adjusted to the height of the upper end of the fixed lower punch 7, and the upper punch 5 is moved upward to remove the part 1 from the mold. The molded part 1 removed from the mold is taken out by, for example, a lateral feed operation of the powder feeding shoe 21. The above-described operation is repeated to sequentially perform powder compacting.
a is formed integrally with the outer lower punch 3 having the notch 9, so that a thin lower punch corresponding to the step width of the flange portion 1b is constructed so as to slide up and down. By using the outer lower punch 3 with a large thickness to increase its rigidity compared to the case where seizure with the die corresponding to the above occurs, deformation due to press pressure is small and the occurrence of seizure is prevented beforehand. doing. In addition, the outer lower punch 3 of the lower punch 4 is relatively moved with respect to the inner lower punch 2, and the inner lower punch 8 of the inner lower punch 2 is press-formed while moving to form a uniform inner compressed density. Is obtained. In the above embodiment, since the shape of the stepped circular component 1 has the lower surface protrusion 1f in addition to the flange portion 1b, the inner lower punch 2 is fixed to the lower punch in order to form the protrusion 1f. 7 and inner lower punch 8
However, in the case of the shape without the projection 1f, the inner lower punch 2 may be constituted only by the movable inner lower punch 8. When the number of steps of the component 1 is larger, it is necessary to increase the number of movable inner lower punches 8 according to the number of steps. Further, the component 1 requires the core rod 6 because the through hole 1c is formed at the center, but the core rod 6 is not required in the case of a solid shape. On the other hand, formation of irregularities such as splines or key grooves on the inner and outer peripheral surfaces of the component 1 can also be performed by changing the design of each molding surface.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded cross-sectional view of a main part of a powder press apparatus according to an embodiment of the present invention in a press finished state. [FIG. 3] Cross-sectional view of the relevant part in the ejected state [Description of reference numerals] 1 Circular component 1a Outer peripheral surface 1b Flange 2 Inner lower punch 3 Outer lower punch 3a Molding surface 4 Lower punch 5 Upper punch 5a Molding surface 6 Core rod 7 Fixed lower punch 7a Forming surface 8 Inner lower punch 8a Forming surface 9 Notch 10 Guide plate 20 Press mechanism

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B30B 11/02 B22F 3/035

Claims (1)

(57) [Claims] A powder press apparatus for compacting a stepped circular component having a step on the outer periphery of a cylindrical surface whose center line extends in the vertical direction, wherein the outer peripheral surface of the outermost step and the outermost step of the outermost step in the component are formed. It has a bottom surface and a molding surface corresponding to the shape of the outer peripheral surface following the lower part of this outermost step , and can be moved up and down
An outer lower punch supported from the lower end by the outer punch plate , and an inner lower support having a molding surface corresponding to the shape of the bottom surface other than the above, and supported by the inner punch plate.
An outer punch and an inner lower punch.
Lower punch is formed with a punch is arranged relatively movably on the outside of the outer lower punch, the outer periphery thereof
A ring-shaped guide plate that guides the surface up and down
Is arranged, with respect to the lower punch, upper punch with a shaped surface corresponding the upper to the shape of the upper surface of the component is arranged axially pressurizable move relative to the lower punch A powder press device characterized by the above-mentioned.