CN114799167A

CN114799167A - Die device for powder molding

Info

Publication number: CN114799167A
Application number: CN202111295146.XA
Authority: CN
Inventors: 犬塚智宪
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 2021-01-21
Filing date: 2021-11-03
Publication date: 2022-07-29
Also published as: JP2022112155A

Abstract

A die device for powder molding includes: a stamper which is a mold; a die plate provided with the die; a heating unit provided in the die plate for heating the die; a lower punch plate provided with a lower bushing; a die-pressing rod inserted into the lower bushing to movably connect the die plate and the lower punch plate to each other; and an auxiliary die rod provided outside the heating unit in the die plate and fitted into a lower guide connected to the lower punch plate, wherein when the die is not heated, a gap is provided between the die rod and the lower bushing, the die rod and the lower bushing are arranged in a non-contact state, and the lower guide fitted into the auxiliary die rod is arranged in a non-thermal expansion direction of the die plate.

Description

Die device for powder molding

Technical Field

The present invention relates to a die device for powder molding, which can be used for warm compaction powder molding.

Background

In powder metallurgy, warm compaction powder forming is widely used in which raw material powder mainly composed of a metal such as iron is heated and compacted. In warm compaction powder molding, a die is heated by a heating means such as a heater, but heat from the heating means is transmitted to a die plate, and the entire die plate may be deformed by thermal expansion. As a result, the upper end position of the die rod (guide rod) connected to the die plate is changed, and the lower bush fitted to the die rod is quickly engaged, and there is a possibility that a malfunction occurs in the die apparatus for warm compaction powder molding (warm compaction powder molding die).

Accordingly, in japanese patent laid-open No. 10-204504, as a means for preventing thermal deformation, a method of providing an air insulation layer between a die holder and a die plate of the die plate is disclosed.

Disclosure of Invention

However, when a powder which is difficult to mold, such as a nanocrystal powder or an amorphous magnetic powder, which has been used in recent years, is molded, it is necessary to further heat the stamper at a high temperature (for example, 400 to 600 ℃). Therefore, when heat is insulated only by the air heat insulating layer according to the method described in japanese patent application laid-open No. 10-204504, it may be difficult to prevent thermal deformation of the die plate.

Further, when a powder box or the like is disposed in the apparatus, unevenness in weight balance may occur, the die plate may be inclined, and the die may be engaged with another punch.

The present invention has been made in view of the above problems, and an object thereof is to provide a die apparatus for powder molding in which a die plate is stably arranged and malfunction due to thermal deformation of the die plate can be prevented.

One aspect for achieving the above object is a die device for powder molding, including: a stamper for a mold; a die plate provided with the die; a heating unit provided in the die plate for heating the die; a lower punch plate provided with a lower bushing; a die-pressing rod inserted into the lower bushing to movably connect the die plate and the lower punch plate to each other; and an auxiliary die rod provided outside the heating unit in the die plate and fitted into a lower guide connected to the lower punch plate, wherein when the die is not heated, a gap is provided between the die rod and the lower bushing, the die rod and the lower bushing are arranged in a non-contact state, and the lower guide fitted into the auxiliary die rod is arranged in a non-thermal expansion direction of the die plate.

In the die apparatus for powder molding according to the present invention, since a clearance (clearance) for thermal deformation is provided in advance between the die rod and the lower bush fitted to the die rod, it is possible to prevent rapid occurrence of seizure and a cause of malfunction. In the die device for powder molding according to the present invention, since the auxiliary die rod fitted to the lower guide disposed at the specific position is provided in addition to the die rod, the die plate can be stabilized and each plate can be smoothly operated even when the gap is provided.

In the die plate, it is preferable that a heat insulating unit is provided between the heating unit and the auxiliary die rod.

Preferably, the heating unit, the die-pressing rod, and the auxiliary die-pressing rod are each provided in plurality in an axisymmetric manner with respect to the center of the die.

Preferably, the die rod and the auxiliary die rod are provided in different radial directions and in the same circumferential direction around the center of the die.

Further, it is preferable that the lower guide is provided in plural in a circumferential direction around the center of the die as an axis with respect to one of the auxiliary die rods.

According to the present invention, it is possible to provide a die apparatus for powder molding in which a die plate is stably arranged and malfunction due to thermal deformation of the die plate can be prevented.

Drawings

Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals refer to like elements.

Fig. 1A is a partial plan view of one embodiment of a die device for powder molding according to the present invention.

Fig. 1B is a partial sectional view of one embodiment of the die device for powder molding according to the present invention.

Fig. 2A is a partial plan view of one embodiment of the die device for powder molding of the present invention.

Fig. 2B is a partial sectional view of an embodiment of the die device for powder molding according to the present invention.

Fig. 3A is a front view for explaining a gap portion provided between the die rod and the lower bushing in the present embodiment.

Fig. 3B is a plan view for explaining a gap portion provided between the die rod and the lower bushing in the present embodiment.

Fig. 4A is a plan view of the auxiliary die rods in the die plate for explaining the fitting portions of the auxiliary die rods and the lower guide in the present embodiment.

Fig. 4B is a plan view of the fitting portion of the auxiliary die lever shown in fig. 4A.

Fig. 4C is a side view of the fitting portion of the auxiliary die lever shown in fig. 4A.

Fig. 5A is a plan view of the auxiliary die rods in the die plate for explaining the fitting portions of the auxiliary die rods and the lower guide in the present embodiment.

Fig. 5B is a plan view of the fitting portion of the auxiliary die lever shown in fig. 5A.

Fig. 5C is a side view of the fitting portion of the auxiliary die lever shown in fig. 5A.

Detailed Description

As described above, if the stamper is heated by a heating means such as a heater, heat is transferred to the stamper plate, and the stamper plate thermally expands. If no measure is taken against this, the die rods connected to the die plate and the lower bush fitted to the die rods may be engaged with each other quickly, and malfunction may occur. In the die apparatus, there is a possibility that the weight balance (for example, in the front-rear direction) becomes uneven due to a powder box or the like, and thereby the die plate may be inclined, and the die may be engaged with another punch.

Therefore, as in japanese patent application laid-open No. 10-204504, a method of preventing the above-described thermal expansion by disposing a heat insulating means (specifically, an air heat insulating layer) between a heating means (specifically, a die holder) and a die plate, and a method of preventing thermal deformation of the die plate using a cooling medium or the like are considered. However, the former method may not sufficiently prevent the thermal expansion depending on the kind of the powder raw material used (for example, a powder which is not easily molded and needs to be molded at a high temperature). In addition, the latter method requires installation of a cooling pipe and a temperature control device therefor, and may be difficult to realize from the viewpoint of ensuring cost and installation area. In addition, in the case of using the above-described powder which is not easily molded in the latter method, temperature control is more difficult, and thermal deformation of the die plate may become further large from the viewpoint of cooling efficiency.

On the other hand, in the die apparatus for powder molding according to the present invention (hereinafter, sometimes referred to as the present apparatus), the die rod and the lower bush are provided with an appropriate clearance (clearance) in advance so as not to cause engagement due to the heating temperature of the die and the temperature of the die plate. In the present apparatus, an auxiliary die bar (other die bars) is provided in the die plate, in addition to the die bar connected to the pressurizing member, via a heat insulating means such as a heat insulating material as needed, in, for example, the front-rear left-right direction (the vertical left-right direction on the paper surface shown in fig. 1A). In this case, the auxiliary die rods are arranged only in a specific direction, specifically, in the non-thermal expansion direction of the die plate, so that the auxiliary die rods can be held in the fitted state without causing engagement with the lower guides during heating of the die. Thus, in the present apparatus, there is no need to provide a gap particularly between the auxiliary die rod and the lower guide.

As described above, the present apparatus does not require a device such as a die cooling device, can stably arrange the die plate at low cost with a simple structure, and can prevent malfunction due to thermal deformation of the die plate. Further, in the present apparatus, it is possible to prevent the die plate from being thermally deformed, cracked, engaged, and abnormally worn by heating the die, to extend the life of the apparatus, and to perform the die molding with high accuracy.

Hereinafter, a specific embodiment to which the present invention is applied will be described in more detail with reference to the drawings. However, the present invention is not limited to these embodiments. In addition, the description and drawings in the present specification are appropriately simplified to clarify the description.

< mold device for powder Molding >

The die device for powder molding according to the present invention can be used for warm compaction powder molding in which a powder material is compacted in a heated state. Since the warm compaction powder molding is performed in a state where the powder material is heated, the density and strength of the powder can be increased even if the powder is pressurized in an unheated state at the same pressure, and the powder can be prevented from being damaged and can be mechanically processed before sintering. In warm compaction powder molding, the temperature of the powder raw material is prevented from decreasing by heating the compaction die using a heater or the like. The type of the powder material to be used in the present apparatus is not particularly limited, and can be appropriately selected, and for example, a powder material which is difficult to mold and needs to be molded at a high temperature can be suitably used.

As shown in fig. 1A and 1B and fig. 2A and 2B, the present apparatus includes a die 1, a die plate 2, a heating means 3 such as a heater, a die rod 4, a lower punch plate 5, a lower bush 6, an auxiliary die rod 7, and a lower guide 8. The apparatus may further include a heat insulating material 9, an upper guide 10, a guide post 11, a die holder 12, an upper punch 13, a yoke plate 14, and an upper punch plate 17. In the present apparatus, an upper punch and a lower punch corresponding to the shape of the member may be disposed in the

parts

15 and 16, respectively. Fig. 1A and 1B and fig. 2A and 2B are views showing an embodiment of the present apparatus, fig. 1A and 2A are partial plan views of the embodiment, and fig. 1B and 2B correspond to partial sectional views taken along line a-a shown in fig. 1A. Further, the structure of the lower mold portion described in detail below may be applied to the upper mold portion as necessary.

In the present apparatus, a conventionally known structure of, for example, a warm-pressing powder molding die apparatus can be applied to a structure other than the auxiliary die rod disposed in the die plate via the heat insulating means and the gap portion between the die rod and the lower bushing as needed, within a range in which the effects of the present invention can be obtained. Therefore, the following description will be given mainly focusing on these characteristic structural portions of the present apparatus, and description of other structural portions may be omitted.

The die 1 used as the mold may be any conventionally known one, and may be set appropriately according to the shape and material of the product to be produced, and is not particularly limited.

The die plate 2 shown in fig. 1A and 1B is provided with a die 1, a die holder 12 for fixing the die 1, a heating unit 3 (heating unit), a die rod 4, an auxiliary die rod 7, a heat insulating unit 9 such as a heat insulator, and an upper guide 10 for fitting a guide post 11.

The heating means 3 is not particularly limited as long as it can heat the stamper 1, and conventionally known members can be appropriately used, and for example, a heater or the like can be used.

The die rod 4 is inserted into the lower bushing 6, and movably couples the die plate 2 and the lower punch plate 5 provided with the lower bushing 6 to each other. In the present apparatus, as shown in fig. 3A and 3B, when the die 1 is not heated by the heating means 3, that is, when it is not heated, a gap is provided between the die rod 4 and the lower bush 6, and the die rod 4 and the lower bush 6 are arranged in a non-contact state. The interval of the gap is not particularly limited, and may be appropriately set according to various conditions such as the type of the powder material to be used, the heating temperature of the die, the amount of thermal expansion of the die plate, and the stability of the die plate. In the embodiment shown in fig. 3A and 3B, for example, the inner diameter (width) W1 of the lower bushing 6 can be made 60mm in diameter, and the width W2 of the die rod 4 can be made 56mm in diameter. In this case, the interval (clearance C1) between (the outer diameter of) the die rod 4 and (the inner diameter of) the lower bush is 2 mm. This embodiment is also suitable for use in warm compaction powder molding in which a stamper is heated to, for example, 450 ℃. In this way, in the present apparatus, since the die rod 4 is fitted to the lower bushing 6 with a gap therebetween, occurrence of seizure and the like can be prevented, and as a result, malfunction due to thermal deformation of the die plate can be easily prevented. In the present apparatus, in order to suppress the influence of the thermal deformation of the die plate, a conventionally known heat insulating means (for example, a heat insulating material or an air heat insulating layer) may be disposed between the die rods 4 and the heating means 3 in the die plate. In this case, the clearance between the die rod 4 and the lower bush 6 can be further reduced.

Fig. 3A and 3B are views for explaining a gap portion provided between the die rod and the lower bushing in the present embodiment, fig. 3A is a front view thereof, and fig. 3B is a plan view thereof.

The auxiliary die rods 7 are provided outside the heating unit 3 (on the outer peripheral side in fig. 1A) in the die plate 2, and are fitted into the lower guides 8 connected to the lower punch plate 5. Here, as shown in fig. 1A, 1B, 2, 4, and 5, the lower guide 8 fitted to the auxiliary die rod 7 is disposed only in the non-thermal expansion direction of the die plate 2. In addition, reference numerals 7a to 7d denote a front auxiliary die-pressing lever, a rear auxiliary die-pressing lever, a right auxiliary die-pressing lever, and a left auxiliary die-pressing lever, respectively. Fig. 4A to C and fig. 5A to C are views for explaining the fitting portions of the front auxiliary die lever 7a and the right auxiliary die lever 7C with the lower guide 8, respectively.

Here, the non-thermal expansion direction of the die plate means the following direction: when the stamper 1 is heated by the heating unit 3, the heat is transferred to the stamper plate 2 to be thermally expanded, and a rate of change due to the thermal expansion is small. Thus, the die plate can also thermally expand in the non-thermal expansion direction, but the effect thereof is small compared to the other directions. For example, in fig. 4A showing the structure of the front auxiliary die rod 7a, the thermal expansion direction of the die plate affected by the front auxiliary die rod 7a is the front-rear direction (the vertical direction on the paper surface), and the lateral direction (the lateral direction on the paper surface) is relatively unaffected by thermal expansion. Therefore, as shown in fig. 4B and 4C, the lower guide 8 is fitted to the front auxiliary die rod 7a only in the left-right direction. Fig. 4B is a plan view for explaining a fitting portion of the front auxiliary die lever 7a and the lower guide 8 shown in fig. 4A, and fig. 4C is a side view when fig. 4B is viewed from a direction B1.

Here, the width W3 of the lower guide, the width W4 of the front auxiliary die lever, and the like may be appropriately set, and are not particularly limited. However, for example, W3 may be set to 120.04+0.01/0mm, and W4 may be set to 120.00/-0.01 mm. In the case of this embodiment, the clearance C2 between the auxiliary die lever and the lower guide is 0.02 mm.

Similarly, fig. 5A shows a structure of a right auxiliary die lever 7c in which a lower guide is fitted only in the front-rear direction (the vertical direction of the paper surface) which is relatively unaffected by thermal expansion of the die plate. The W5, W6, and C3 may be appropriately set, and are not particularly limited, but may be formed in the same manner as W3, W4, and C2 in fig. 4A to C, for example. Fig. 5B is a plan view for explaining a fitting portion between the right auxiliary die lever 7C and the lower guide 8 shown in fig. 5A, and fig. 5C is a side view when fig. 5B is viewed from a direction B2.

As shown in the plan views of fig. 1A and 1B and fig. 2A and 2B, the heating unit 3, the die rod 4, and the auxiliary die rod 7 are provided in plural numbers so as to be axisymmetric with respect to the center of the die 1 (central axis). The die rods 4 and the auxiliary die rods 7 are provided in different radial directions and in the same circumferential direction around the center of the die 1. Further, a plurality of lower guides 8 are provided with respect to one auxiliary die lever 7 in the circumferential direction around the center of the die 1 as an axis. That is, in this embodiment, the thermal expansion direction may be referred to as a radial direction, and the non-thermal expansion direction may be referred to as a circumferential direction. In this way, in the present apparatus, since the auxiliary die rods and the lower guide are provided in a specific arrangement, the auxiliary die rods can be prevented from being positionally displaced by the thermal expansion of the die plate and from being engaged with the lower guide, and further, the die plate can be prevented from being inclined. In the embodiments shown in the figures, the stamper 1 having a circular planar shape is used, but a stamper having another shape may be used, and the shape, arrangement, number of other members (components) constituting the device, and the like can be appropriately set in accordance therewith.

In the present apparatus, from the viewpoint of further suppressing the influence of the thermal expansion of the die plate, the heat insulating means 9 may be provided between the heating means 3 and the auxiliary die rods 7 in the die plate 2. As the heat insulating means, conventionally known members can be suitably used, and various members such as a heat insulating material and an air insulating layer can be used. In this way, in the present apparatus, the auxiliary die rod 7 can further suppress thermal deformation by the heat insulating means, and therefore, it is not necessary to provide a relatively large gap between the die rod 4 and the lower bush 6, and the plate can be stably operated.

Therefore, in the apparatus, when not heated, the die rods are inserted into the lower bush with a gap, and the auxiliary die rods are inserted into the lower guide without providing a large gap.

In addition, the present apparatus may be provided with a detachable positioning jig for determining the position of the presser connecting the die rod and the lower bush, as necessary, at the time of setting change or the like.

As described above, according to the invention according to the present embodiment, it is possible to provide a die apparatus for powder molding in which the die plate is stably arranged and in which malfunction due to thermal deformation of the die plate can be prevented. The die device for powder molding according to the present invention can be used for manufacturing sintered parts for vehicles such as automobiles, for example, but is not limited to this application. The present invention is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the gist of the present invention.

Claims

1. A die device for powder molding, comprising:

a stamper for a mold;

a die plate provided with the die;

a heating unit provided to the die plate for heating the die;

a lower punch plate provided with a lower bushing;

a die-pressing rod inserted into the lower bushing to movably connect the die plate and the lower punch plate to each other; and

an auxiliary die-pressing rod provided outside the heating unit in the die plate and fitted into a lower guide connected to the lower punch plate,

a gap is provided between the die rod and the lower bushing when the die is not heated, the die rod and the lower bushing are arranged in a non-contact state,

the lower guide fitted to the auxiliary die press rod is disposed along a non-thermal expansion direction of the die press plate.

2. The die apparatus for powder molding according to claim 1, wherein a heat insulating unit is provided between the heating unit and the auxiliary die rod in the die plate.

3. The die apparatus for powder molding according to claim 1 or 2, wherein the heating unit, the die rod, and the auxiliary die rod are each provided in plural numbers in axisymmetric relation with respect to a center of the die.

4. The die set for powder molding according to any one of claims 1 to 3, wherein the die-pressing rod and the auxiliary die-pressing rod are provided in different radial directions and in the same circumferential direction, respectively, with the center of the die as an axis.

5. The die apparatus for powder molding according to any one of claims 1 to 4, wherein a plurality of the lower guides are provided with respect to one of the auxiliary die rods in a circumferential direction around a center of the die.