JPH072280B2 - Powder press equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a powder press device for powder compacting a stepped circular part having a step portion on the outer periphery of a cylindrical surface whose center line extends in the vertical direction. .

(Prior Art) In general, when manufacturing a powder sintered part or the like, it is first necessary to compress the powder into a predetermined shape by a powder press machine. In the case of a circular part, the outer peripheral surface is molded with a cylindrical die, and the upper and lower end surfaces are molded 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 pressing apparatus that has been generally adopted in the related art, there is a risk that seizure may occur in a part of the punch due to repeated press molding.

That is, in the case of a circular part having steps with different diameters on the outer circumference of the cylindrical surface, in order to make the compression density uniform in each part of the product after molding, the lower punch corresponding to each step has a cylindrical shape. The outer part of the lower punch moves according to the length of the lower punch as the lower punch moves downward, and the ratio of the height filled with powder before compression and the product height after compression is It is made uniform in each step. In the case of a flange-shaped step portion, when the step thickness is thin, that is, when the amount of protrusion in the diametrical direction due to the diameter change is small, the thickness of the punch member in this portion is also thin and the rigidity is low, and the compression pressure in the pressing process is small. The punch member is deformed by acting so as to expand to the outside, and its outer peripheral portion slides relatively to the inner peripheral surface of the outer die in a state of strong pressure contact. By repeating this press molding, sliding streaks may be generated in the vertical direction on the contact surfaces of the two, and finally seizure may occur.

(Object of the Invention) In view of the above circumstances, the present invention provides a powder pressing apparatus that improves the rigidity of the lower punch and reduces the deformation due to pressing pressure to prevent the occurrence of seizure in the punch. The purpose is.

(Structure of the Invention) The powder pressing apparatus of the present invention comprises an outer peripheral surface of an outermost step portion and a bottom surface of the outermost step portion in a stepped circular part having a step portion on the outer periphery of a cylindrical surface whose center line extends in the vertical direction. And an outer lower punch having a forming surface corresponding to the shape of the outer peripheral surface following the lower part of the outermost peripheral step, and an inner lower punch having a forming surface corresponding to the shape of the outer peripheral surface other than the above and the bottom surface other than the above. Movably arranged to form a lower punch, and the outer periphery of the outer lower punch is supported by a guide plate, and a molding surface corresponding to the shape of the upper surface of the component is attached to the lower punch from above. It is characterized in that the upper punch that is provided is arranged so as to be capable of pressurizing and moving in the axial direction with respect to the lower punch.

(Effects of the Invention) According to the present invention, the outer lower punch has a large thickness, has high rigidity, is less likely to be deformed by the press pressure, and can prevent sliding seizure on the outer peripheral surface thereof.
Good powder compacting can be performed over a long period of time.

(Examples) Examples 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 part 1 to be compacted has a flange portion 1b (outermost step portion) protruding to the upper outer periphery of the outer peripheral surface 1a as a cylindrical surface whose center line extends in the vertical direction, and has a through hole in the center portion. 1c
Is formed, the upper end surface 1d is substantially flat, and the lower end surface 1e is provided with a protrusion 1f projecting in the axial direction on the center side.

The above-mentioned component 1 is formed by forming a lower punch 4 including an inner lower punch 2 and an outer lower punch 3 for forming a bottom surface portion and a peripheral surface portion of the component 1 and a lower end forming surface 5a of the component 1 by pressurizing from above. Upper punch 5 for molding the upper surface 1d
And the core rod 6 that forms the through hole 1c at the center in the outer peripheral surface
This is done with and.

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 projection 1f of the component 1, and an inner peripheral surface and a lower end surface 1e for forming the peripheral surface of the projection 1f. Inner lower punch 8 having each end forming surface 8a
It consists of and.

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 peripheral surface of the flange portion 1b. That is, the molding surface 3a is composed of an inner peripheral molding surface corresponding to the outer peripheral surface 1a of the component 1, and a cutout portion 9 forming a concave molding 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 inner side to the outer side. 3 are provided so as to be vertically slidable in the axial direction. A ring-shaped guide plate 10 that supports the outer peripheral surface of the outer lower punch 3 is slidably arranged outside the outer lower punch 3.

The supporting structure of each of the punches 2 to 4 is shown in FIG. 2, which shows a powder filling state before pressing. The fixed lower punch 7 of the inner lower punch 2 has a pipe-shaped lower end portion as a first portion.
It is supported in a fixed state by being supported by a cylindrical fixed base 13 via a plate 12. The core rod 6 penetrating the inside of the fixed lower punch 7 penetrates the first plate 12 and is connected to and supported by the core 14 in the fixed base 13.
It is slid at the time of ejecting.

On the other hand, the lower ends of the inner lower punch 8 and the outer lower punch 3 are connected and supported by the bottom platen 17 and the standard platen 18 via the second plate 15 and the third plate 16, respectively. Also, the guide plate
10 is further supported by a top platen 19 on the outer peripheral portion. Further, the upper punch 5 has its upper end connected to and supported by the press mechanism 20.

Further, the bottom platen 17 and the standard platen 18 are configured so that the descending position at the time of pressing is restricted by a press stop (not shown), and this press stop is configured to release the restriction after the press and shift to the eject operation. . The bottom platen 17 and the standard platen 18 are lift cylinders (not shown).
Are provided respectively and are moved up and down to a predetermined position, and are urged upward during pressing to move downward according to the pressing operation of the upper punch 5.

Further, in order to supply the powder P, the above-mentioned top plate 19
A powder feeding shoe 21 which is in contact with the upper surface of and is slidable in the lateral direction is installed.

The operation of the above configuration will be described. First, in the case of supplying the powder P for performing the powder compacting, as shown in FIG.
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, and the tip end of the core rod 6 and the outer lower punch 3 are moved.
Upper end face and guide plate 10 (top platen 19)
Make the upper end surface flush with the top surface of the powder feeding shoe 21
Is moved to fill the space portion formed on the outer peripheral portion of the core rod 6 with the powder P. At this time, the shape of the space is the same as that of the component 1.
With respect to the product size of (1), it is set by enlarging in the vertical direction so that a predetermined compression ratio is obtained in each part.

Next, the upper punch 5 is pressed by the pressing force of the press mechanism 20.
The lower end molding surface 5a comes into contact with the upper surface of the powder P, and further descends 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 dimensions of the component 1 as shown in FIG.

Then, the eject operation is started, and the outer lower punch 3 and the inner lower punch 8 are further lowered by a cylinder (not shown) by releasing the press stop. As a result, 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 inner lower punch 8, the outer lower punch 3 and the core rod 6 are removed. While adjusting the upper end height to the upper end height of the fixed lower punch 7,
The upper punch 5 is lifted and the component 1 is demolded. The demolded and molded part 1 is taken out by, for example, the lateral feeding operation of the powder feeding shoe 21.

The above-mentioned operation is repeated to perform powder compaction one by one. The outermost step of the component 1, that is, the peripheral surface and the bottom surface of the flange portion 1b, and the punch for forming the outer peripheral surface 1a continuous with the punch are cut out. Since the outer lower punch 3 having 9 is integrated, conventionally, a thin lower punch corresponding to the step width of the flange portion 1b is configured to slide up and down to cause seizure with a die corresponding to the guide plate 10. On the other hand, by increasing the thickness of the outer lower punch 3 to increase its rigidity, the deformation due to the press pressure is small and the occurrence of seizure is avoided.

In the above embodiment, the stepped circular component 1 has a lower surface protrusion 1f in addition to the flange portion 1b.
The inner lower punch 2 is composed of the fixed lower punch 7 and the inner lower punch 8 in order to form the protrusion 1f. However, in the case of the shape without the protrusion 1f, the inner lower punch 2 is formed only by the fixed lower punch 7. Should be configured. Further, when the number of steps of the component 1 is further increased, it is necessary to increase the number of movable inner lower punches 8 in accordance with the number of steps. Further, in the component 1, the through hole 1c is formed at the center.
Since the core rod 6 is required to form
In the case of a solid shape, the core rod 6 becomes unnecessary. on the other hand,
The 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 drawings]

FIG. 1 is an exploded cross-sectional view of a main part of a powder pressing apparatus in a pressed state in one embodiment of the present invention, FIG. 2 is a cross-sectional view of a main part of the powder pressing apparatus before pressing, and FIG. 3 is an ejecting state. It is a principal part sectional drawing. 1 …… Circular part, 1a …… Outer peripheral surface 1b …… Flange part, 2 …… Inner lower punch 3 …… Outer lower punch, 3a …… Molding drawing 4 …… Lower punch, 5 …… Upper punch 5a …… Molding Fig. 6 …… Core rod 7 …… Fixed lower punch, 7a …… Molding surface 8 …… Inner lower punch 8a …… Molding surface, 9 …… Notch 10 …… Guide plate, 20 …… Pressing mechanism

Claims (1)

[Claims] 1. A powder pressing apparatus for powder compacting a stepped circular part having a step portion on the outer periphery of a cylindrical surface whose center line extends in the vertical direction, the outer peripheral surface of the outermost step portion of the part and the outer peripheral surface of the step portion. An outer lower punch having a bottom surface of the outermost peripheral step portion and a forming surface corresponding to the shape of the outer peripheral surface following the lower portion of the outermost peripheral step portion, and an outer peripheral punch other than the above and a forming surface corresponding to the shape of the bottom surface other than the above. The inner lower punch is movably arranged to form a lower punch, the outer periphery of the outer lower punch is supported by a guide plate, and the shape of the upper surface of the component from the upper side with respect to the lower punch. A powder press device, wherein an upper punch having a molding surface corresponding to is disposed so as to be axially movable with respect to the lower punch.