JP6183689B2 - Powder mold - Google Patents

Description

  The present invention relates to a powder molding die used for pressure molding of raw material powder in a manufacturing process of a sintered part.

  In a powder molding machine used in the manufacture of sintered parts, a powder molding die (hereinafter simply referred to as a metal mold) that has a die, an upper punch, and a lower punch as basic elements, and a core rod that molds a hole in the part as needed is added. Type).

  The upper punch and the lower punch are divided into a plurality of parts depending on the shape of the end face of the sintered part. For example, the following Patent Document 1 describes a mold in which a lower punch is divided.

  An example of a mold obtained by dividing the upper punch is shown in FIGS. The illustrated mold is a combination of a die 1, an upper 1 punch 2, an upper 2 punch 3, a lower punch 4 facing the upper punch, and a core rod 5.

  The upper 2 punch 3 is incorporated in a groove 6 provided on the inner peripheral side of the upper 1 punch 2. The upper 2 punch 3 forms a recess 11 provided at a location where the upper surface and the inner peripheral surface of the molded body 10 obtained by pressure-molding the raw material powder intersect.

  The illustrated recess 11 includes a bottom surface that is inclined with respect to the axis of the punch, and the inclined bottom surface is formed by a molding surface 3 f provided on the upper two punches 3.

  The upper 2 punch 3 can be formed integrally with the upper 1 punch 2 if the depth in the axial direction of the recessed portion to be formed is shallow, so it is not necessary to divide the upper 2 punch 3. If it is deep to some extent, the molding density locally increases, so the upper 2 punch 3 must be divided from the upper 1 punch 2.

JP 2010-82671 A

  In the mold shown in FIGS. 6 and 7, a side pressure in the direction of pressing the upper 2 punch 3 against the core rod 5 is applied from the molded body 10 to the upper 2 punch 3 when the powder is molded. When the upper punch 3 has an inclined molding surface 3f as in the illustrated mold, the lateral pressure is particularly large.

  If the upper 2 punch 3 is small with respect to the pressing force and the ability to prevent bending is low, the upper 2 punch 3 is pressed against the core rod 5 with a strong force. In this state, the upper 2 punch 3 and the core rod 5 move relative to each other in the axial direction, so that problems such as wear and seizure of the sliding surfaces of both occur.

  With respect to this problem, Patent Document 1 described above is provided with an inclined surface that generates a component force in a direction to cancel the side pressure with respect to the punch receiving the side pressure from the molded body.

  However, if the punch that receives the lateral pressure cannot form a slope for canceling the lateral pressure, or if the punch can be formed and the punch is small in size, the area of the slope cannot be secured sufficiently. Method 1 cannot be used.

  It is an object of the present invention to prevent a split punch that receives a side pressure during powder molding from being pressed tightly against a sliding mating mold element such as a core rod to prevent wear or seizure on a sliding surface. .

  In order to solve the above problems, in the present invention, a die, an upper punch, and a lower punch are provided, and at least one of the upper punch and the lower punch is configured by a plurality of divided punches, and a molded body ( A divided punch that receives a side pressure from a powder in the middle of molding (which is also considered as a molded body in the cavity) (here, for convenience of explanation, this is referred to as a divided punch B) is included. This was called a split punch A), and the following contrivances were applied to the mold, which was a powder molding mold inserted in a groove provided corresponding to the divided punch A).

  That is, the divided punch B is provided with a locking projection protruding in the circumferential direction, and the locking projection is inserted into the widened portion provided in the groove of the divided punch A so that the divided punch B becomes the divided punch A. On the other hand, they were engaged so as not to move in the radial direction.

  In the powder molding die of the present invention, the radial movement of the divided punch B is prevented by the divided punch A, so that the sliding surface of the mold element is not worn or seized.

It is sectional drawing which shows an example of the powder shaping die of this invention. It is sectional drawing of the top punch along the II-II line of FIG. It is sectional drawing which shows the compacting completion state in the powder molding die of FIG. It is sectional drawing which shows the other example of the powder shaping die of this invention. It is a perspective view of the molded object obtained by shape | molding with the powder shaping die of FIG. It is sectional drawing which shows an example of the conventional powder molding metal mold | die. It is sectional drawing of the upper punch along the VII-VII line of FIG.

  Embodiments of the powder molding die according to the present invention will be described below with reference to FIGS.

  The powder molding die in FIG. 1 is for molding the molded body 10 shown in FIG. 5 and includes a die 1, an upper 1 punch 2, an upper 2 punch 3, a lower punch 4 facing the upper punch, and a core rod. It is a combination of five.

  The upper 2 punch 3 is incorporated in a groove 6 provided on the inner peripheral side of the upper 1 punch 2 at a portion not involved in molding. Further, a portion involved in the molding is protruded downward by a predetermined amount from the lower end (tip) of the upper punch 2. This structure is not different from the conventional mold shown in FIG.

  In addition, the two punches 3 form a recess 11 provided at a location where the upper surface and the inner peripheral surface of the molded body 10 obtained by pressure-molding the raw material powder intersect. This is the same as the conventional mold shown in FIG.

  The amount of protrusion of the upper 2 punch 3 from the lower end of the upper 1 punch 2 is equal to the depth d of the recess 11 (see FIG. 3) provided in the molded body 10.

  When the depth d of the concave portion 11 exceeds, for example, 20% of the axial length of the molded article to be manufactured, the portion for molding the concave portion of the punch (the upper two punches 3 in the illustrated mold correspond to that). ) Is divided to prevent a local density increase of the molded body.

  In the powder molding die of FIG. 1, a locking projection 7 bulging in the circumferential direction is provided in a region not involved in the molding of the upper 2 punch 3.

  Further, the groove 6 of the upper punch 2 is provided with a widened portion 8 (see FIG. 2) corresponding to the locking convex portion 7 so that the size of the groove 6 is similar to the shape perpendicular to the axis of the upper punch 3 and the size is adapted. The upper punch 2 is inserted into the groove 6. This configuration is different from the conventional product.

  The upper 2 punch 3 provided with the locking projection 7 is engaged with the widened portion 8 of the upper 1 punch 2 so as not to move in the radial direction, and is held in the radial direction by the upper 1 punch 2. This prevents the upper 2 punch 3 from being displaced inward in the radial direction, and the upper 2 punch 3 and the core rod 5 are pressed against each other, in other words, in a state in which a strong frictional force is generated on the sliding surfaces of both. It will not move.

  The circumferential protrusion amount t (see FIG. 2) and the width w of the locking convex portion 7 are set to dimensions that give strength sufficient to withstand the side pressure in consideration of the side pressure applied to the upper two punches 3 during molding.

  If the shape of the locking convex portion 7 may be transferred to the molded body 10, the locking convex portion 7 is provided to extend to the protruding portion from the lower end of the upper 1 punch of the upper 2 punch 3. Can do.

  In this case, if the locking projection 7 is too large, the area of the end face of the molded body 10 is unnecessarily reduced. Therefore, it is preferable to make it as small as possible within the range that can withstand the assumed side pressure.

  In the case of a mold for producing a molded body having an outer diameter of 100 mm, an inner diameter of 35 mm, a height of 30 mm, and a circumferential width of the concave portion of 4 mm, the protruding amount t of the locking convex portion 7 is about 1 mm and the width w is 3 Even at about 4 mm, the upper 2 punch 3 was retained by the upper 1 punch 2 without any problem.

  When the shape of the locking projection 7 is disliked from being transferred to the molded body 10, the locking projection 7 is provided in a region arranged above the lower end of the upper 1 punch 2.

  Note that the relative movement in the axial direction of the upper 1 punch 2 and the upper 2 punch 3 does not occur in the final stage of compression that receives a strong lateral pressure.

  Therefore, the upper 1 punch 2 and the upper 2 punch 3 are not rubbed and worn or burned.

  In the powder molding die of FIG. 4, the upper 2 punch 3 is incorporated in a groove 6 provided on the outer peripheral side of the upper 1 punch 2. In the mold having this structure, the upper two punches 3 are pressed against the die 1 by receiving a side pressure from the molded body.

  Therefore, in the powder mold shown in FIG. 4, the upper two punches 3 are provided with locking projections 7, and the locking projections 7 are inserted into the widened portion 8 provided in the groove 6, so The pressing against the die 1 is prevented.

  Thus, when the recessed part provided in a molded object is provided in the cross | intersection part of the upper surface and outer peripheral surface of a molded object, the upper 2 punch 3 is integrated in the groove | channel provided in the outer peripheral side of the upper 1 punch 2. Become.

  In the above description, the upper punch is divided as an example. However, in the present invention, the lower punch is divided, or both the upper punch and the lower punch are divided. It can also be applied to things.

  The effectiveness of the present invention is exhibited if the die includes a part punch that receives a side pressure from the molded body.

DESCRIPTION OF SYMBOLS 1 Die 2 Upper 1 punch 3 Upper 2 punch 3f Molding surface 4 Lower punch 5 Core rod 6 Groove 7 Locking convex part 8 Widening part 10 Molded object 11 Concave part

Claims (1)

A die, an upper punch, and a lower punch are provided, and at least one of the upper punch and the lower punch is composed of a plurality of divided punches, including a divided punch that receives a side pressure from a molded body in the cavity, and receives the side pressure. A powder molding die in which a divided punch is inserted into a groove provided in an adjacent divided punch,
The divided punch receiving the lateral pressure is provided with a locking convex portion protruding in the circumferential direction, and the locking convex portion is inserted into the widened portion provided in the groove of the adjacent divided punch to receive the lateral pressure. Is engaged with the adjacent divided punch so as not to move in the radial direction .
Further, the forming part of the divided punch that receives the lateral pressure is protruded from the tip of the adjacent divided punch, and the upper punch is above the protruding part and the lower punch is below the protruding part. Powder molding die provided with protrusions .

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