JP2014083547A - Die unit for powder molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die unit for a powder molding machine, which, even when using a stepped die that is considered anxious to be supported by a die plate due to large load received by the stepped die in a punch axis direction, is assured stable molding by enabling the stepped die to be stably supported.SOLUTION: The die unit for a powder molding machine includes a stepped die 1 having a molding surface 1a for receiving a molding load in a punch axis direction, an upper punch 2 and a lower punch 3. The die unit further includes a movable plate 9 which can be lifted together with a receiving implement 8 and is disposed under the stepped die 1, the stepped die 1 is not fixed to the die plate 5, and the stepped die 1 is also supported by the movable plate 9 via the receiving implement 8.

Description

  The present invention relates to a mold apparatus for a powder molding machine called a die set, and more particularly, to an apparatus having a stepped die having a molding surface for receiving a molding pressure in a pressurizing direction, and supporting the stepped die The present invention relates to a mold apparatus for a powder molding machine with a devised structure.

  Some of the die apparatuses for powder molding machines mentioned above use a stepped die (see, for example, Patent Documents 1 and 2 below). The stepped die has a molding surface that receives a molding pressure in the pressurizing direction (hereinafter referred to as a stepped molding surface for convenience).

  In the mold apparatus including the stepped die, the die is supported by the die plate similarly to the mold apparatus including the die having no stepped surface. The support of the die by the die plate is described in Patent Document 3 below, for example.

  The die plate is supported by a yoke driven by a lower ram of a powder molding machine (press machine). The die plate is connected to the yoke through several connecting rods, thereby supporting the die by the yoke.

JP 2009-148813 A Japanese Patent Laid-Open No. 11-071604 JP 2008-155257 A

  In powder molding using a stepped die, the axial load acting on the die may be very large. On the other hand, the die plate has a limit in strength.

  The die plate is relatively large in size because a powder supply box for putting powder into the cavity of the die is placed on the upper surface. Since the die plate is connected to the yoke via the connecting rod as described above, the die plate is subjected to weight restrictions and the like, and the restrictions cannot increase the thickness and increase the strength freely. Under such circumstances, the maximum load capacity of the die plate of the current mold apparatus is limited to about 200 tons.

  In order to support the die with a die plate with limited load capacity, conventional powder molding machines that use stepped dies have restricted the size and shape of the stepped surface of the die. Therefore, it was necessary to consider the use of a stepped die on which an axial load of about 180 tons acts.

  When such a large axial load is applied to a die plate having a maximum load capacity of 200 tons, the safety factor is low, and the die plate may be damaged.

  Therefore, the present invention provides a stable support for a stepped die even if a stepped die is used that is subjected to a large load in the punch axis direction and is uneasy to support by a die plate. The goal is to ensure stable molding.

  In order to solve the above problems, in the present invention, a mold apparatus for a powder molding machine including a stepped die having a molding surface that receives a molding load in the punch axis direction, an upper punch, and a lower punch, A receiving jig and a movable plate capable of moving up and down are provided below the stepped die, the stepped die is not fixed to the die plate, and the stepped die is inserted into the movable plate via the receiving jig. Supported by. The receiving jig is preferably a cylindrical one surrounding the lower punch.

  The movable plate is connected to a yoke driven by a lower ram of a powder molding press. There are two modes of connection: a structure that is fixed so as not to move relative to the yoke, and a structure that allows the punch shaft (vertical direction) relative movement to the yoke to be allowed via a lifting mechanism such as a cylinder actuator. Can be considered.

  In either case, a die cutting mechanism is attached to take out the obtained molded body from the mold. The die cutting mechanism may be a general mechanism including a support tool that temporarily supports the lower punch plate at a point where the compacting by the punch is completed, and a release unit that releases the support by the support tool.

  If the mold apparatus has only one lower punch, it may be permitted to connect the movable plate supporting the stepped die so as not to move relative to the yoke.

  When a plurality of lower punches are provided, a lower punch plate that supports any one of the lower punches can also be used as the movable plate. In that case, the lower punch plate and the yoke that are also used are connected via an elevation mechanism such as a cylinder actuator that relatively moves both in the punch axis direction.

  In addition, in a mold apparatus that connects the lower punch plate, which is also used, to the yoke so that relative movement in the punch axis direction is allowed, the stepped die and the die plate are combined so as to be capable of relative movement in the punch axis direction. Good. Moreover, it is preferable to interpose a dust seal in the gap between the stepped die and the die plate.

  In the mold apparatus according to the present invention, since the stepped die is supported by the movable plate provided below the die, the molding load in the punch axis direction received by the stepped die is not applied to the die plate. For this reason, the problem of insufficient strength of the die plate does not occur, and even if a stepped die whose support on the die plate is anxious is used, the stable support of the stepped die is made and stable molding is guaranteed. The

Sectional drawing which shows an example of the metal mold | die apparatus for powder molding machines of this invention Sectional drawing which shows the completion | finish state of die-cutting of the molded object in the metal mold apparatus of FIG. Sectional drawing which expands and shows a part of FIG. Sectional drawing which expands and shows a part of FIG. The perspective view of an example of the product (powder compact) shape | molded with the metal mold | die apparatus of FIG.

  Embodiments of a mold apparatus for a powder molding machine according to the present invention will be described below with reference to FIGS. The mold apparatus shown in FIG. 1 is used for forming a toothed ring R as shown in FIG. 5 and includes a stepped die 1, an upper punch 2, a lower punch 3, and a core rod 4. .

  The stepped die 1 has a molding surface 1a (see FIGS. 3 and 4) that enters in the radial direction, and is provided with a molding surface 1a to which a molding pressure in the punch axis direction is applied when molding powder. Yes.

  The illustrated core rod 4 is connected to the yoke 6 via an elevating mechanism (not shown). The elevating mechanism for moving the core rod 4 and the core rod individually up and down is provided as necessary and is an essential element. is not. 5 is a die plate. This die plate 5 is connected to a yoke 6 via a connecting rod 7. The yoke 6 is driven by a lower ram (not shown) of the powder forming press.

  A receiving jig 8 and a movable plate 9 are disposed below the stepped die 1. Reference numeral 10 denotes a fixed base plate (lower punch plate) that supports the lower punch 3. A receiving jig 8 and a movable plate 9 are installed between the base plate 10 and the stepped die 1, and the stepped die 1 is supported by the movable plate 9 via the receiving jig 8.

  The receiving jig 8 has a cylindrical shape. The stepped die 1 is supported by the cylindrical receiving jig 8, and the stepped die is supported by a plurality of interspersed connecting rods or a die plate connected to the yoke via the connecting rods. High support rigidity can be obtained as compared with the form of supporting the die.

  The movable plate 9 of the illustrated mold apparatus is connected to the yoke 6 through an elevating mechanism (a cylinder actuator in the figure) 11 and a plurality of rods 12. Each rod 12 is pushed and pulled by the lifting mechanism 11, and the pushing and pulling causes relative movement in the punch axis direction between the stepped die 1 and the yoke 6.

  Reference numeral 13 in FIG. 1 denotes a support tool that temporarily stops and supports the movable plate 9 that supports the stepped die when the stepped die 1 descends to the compacting completion point.

  The illustrated support tool 13 includes a position-fixed support portion 13 a provided on the base plate 10 and a fork 13 b slidably provided below the movable plate 9. Support at the temporary stop point of the movable plate 9 by the support 13 can be released by the release means 14. The release means 14 shown comprises a cam 14a at the lower end of an ejection rod 15 fixed to the die plate 5 and a cam follower 14b attached to the fork 13b.

  The support 13 and the release means 14 constitute a die cutting mechanism for extracting the powder molded body obtained by molding from the stepped die 1.

  That is, in the stepped die 1, the powder P (see FIG. 3) charged into the cavity C (see FIG. 4) formed between the die, the lower punch, and the core rod by the upper punch 2 entering the die hole is formed. When started, the fork 13b with the yoke 6 descends to a position where it is supported and supported by the support portion 13a (that is, a position where it is supported and supported by the base plate 6), and molding is completed at that position (compact completion point).

  Thereafter, the fork 13b is pushed away by the action of the cam 14a and the cam follower 14b and retracted from the receiving portion by the support portion 13a, whereby the movable plate 9 is further lowered from the compacting completion point to the position of FIG. 2 along with the fork 13b. The molded body A (see FIG. 4) is extracted from the stepped die 1.

  As described above, since the movable plate 9 that receives the molding pressure is supported by the base plate 10, there is almost no weight limit on the movable plate 9, and a high-strength plate having a large thickness can be used as the movable plate 9. For this reason, there is no fear of damage due to the molding load of the movable plate 9.

  The stepped die 1 and the die plate 5 are combined with a gap having a size such that the biting of the powder hardly occurs between them. And the dust seal 16 (refer FIG. 3, FIG. 4) which block | closes a clearance gap near the entrance of the clearance gap between the step die | dye 1 and the die plate 5, and suppresses the penetration | invasion of a powder is installed. In the illustrated apparatus, the dust seal 16 is held by the die plate 5, but the dust seal 16 can also be held by the stepped die 1.

  When the raw material powder used at the time of molding is stainless powder or the like that is highly aggressive to the mold element, it is not preferable that the powder bites into the sliding interface of the mold element. Therefore, the gap between the stepped die 1 and the die plate 5 is intentionally increased to make it difficult for the powder to be caught, and in the structure, the powder easily enters the gap between the molds. Although a dust seal 16 is provided for the purpose of prevention, the dust seal 16 is only a preferred element.

  The movable plate 9 can also serve as the lower punch plate in a mold apparatus provided with a plurality of lower punches. For example, when the lower punch is composed of two members, ie, the lower one punch that is supported by the base plate 10 and the lower two punches that need to be pulled down from the molding position in the die-cutting process, the lower punch is supported via the receiving jig 8. The stepped die 1 can be supported by the lower punch plate.

  The mold apparatus illustrated in FIG. 1 and FIG. The maximum load capacity of the movable plate 9 is 500 tons, the maximum load capacity of the die plate 5 is 200 tons, and the receiving jig 8 is a combination of several cylindrical pieces. The stepped die 1 was supported by the movable plate 9.

  Stainless steel powder was formed using the prototype mold apparatus. In this molding, a molding load of about 180 tons is applied to the stepped die 1 in the punch axis direction.

  As a result, stable molding was repeated, and it was confirmed that it was possible to mold a product that had been abandoned in the past.

DESCRIPTION OF SYMBOLS 1 Stepped die 1a Molding surface 2 which receives axial load 2 Upper punch 3 Lower punch 4 Core rod 5 Die plate 6 Yoke 7 Connecting rod 8 Receiving jig 9 Movable plate 10 Base plate 11 Lifting mechanism 12 Rod 13 Supporting tool 13a Supporting part 13b Fork 14 Release means 14a Cam 14b Cam follower 15 Ejection rod 16 Dust seal R Toothed ring C Cavity P Powder A Molded body

Claims (5)

  A mold apparatus for a powder molding machine, comprising a stepped die (1) having a molding surface (1a) for receiving a molding load in the punch axis direction, an upper punch (2), and a lower punch (3), A receiving jig (8) and a movable plate (9) that can be raised and lowered are provided below the stepped die (1), the stepped die (1) is not fixed to the die plate (5), and A mold apparatus for a powder molding machine in which a stepped die (1) is supported by the movable plate (9) through the receiving jig (8).   The mold apparatus for a powder molding machine according to claim 1, wherein a cylindrical jig surrounding the lower punch is provided as the receiving jig (8).   The movable plate (9) is connected to a yoke (6) driven by a lower ram of a powder molding press, and further a support (13) for supporting the movable plate (9) at a compaction completion point. The mold apparatus for a powder molding machine according to claim 1 or 2, further comprising release means (14) for retracting the support and releasing the support state by the support.   Any of Claims 1-3 in which the raising / lowering mechanism (11) which moves the movable plate (9) and the yoke (6) relatively to a punch axial direction is interposed in the connection part of the said movable plate (9) and a yoke (6). A mold apparatus for a powder molding machine according to claim 1.   The gap between the stepped die (1) and the die plate (5) is sized so as to suppress the biting of powder, and a dust seal (16) for closing the gap is arranged near the entrance of the gap. A mold apparatus for a powder molding machine according to any one of the above.

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