JP2003154495A - Powder molding press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powder molding press which can reliably and promptly be filled up with powders in every corners within a cavity. SOLUTION: The powder molding press is provided with a die frame 7 having the cavity C inside, a powder feeding device to feed the powders P in the cavity C, an upper die and a lower die 9 to compress the powders P filled in the cavity C, a piston 31 for vibration to vibrate the lower die 9 in a vertical direction in the cavity C, and filling control means to feed the powders P into the cavity C while vibrating the lower die 9 in a filling process. The flow property of the powders P is accelerated by giving vibration to the powders P in the cavity C through the lower die 9, so that the powders P reliably fills every corners of the cavity C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder molding press, and more particularly to a powder molding press capable of uniformly filling powder as a raw material into a cavity of a mold. Is.

[0002]

2. Description of the Related Art A powder molding press for filling powder and molding a molded product by uniaxial compression is known. This powder molding press includes a lower die (lower punch), an upper die (upper punch) that can be moved up and down by a hydraulic cylinder, etc., and a metal mold, and the raw material is placed in a cavity formed in the metal mold. As described above, after the powder is filled, the upper die descends and presses the powder with a high pressure to form a molded product. That is,
The volume of the powder is contracted by pressurization, and the powder is entangled and adhered to form the powder.

[0003]

However, in the conventional powder molding press, it is difficult to fill the cavity with the powder at a uniform density, so that the strength of the molded product may not be satisfied in some cases. . More specifically, powders such as ceramics are extremely fine and therefore have low fluidity and are easily entangled. Therefore, for example, when powder is supplied to the center of the cavity, it solidifies near the center,
It was difficult to fill every corner of the cavity.
As a result, the density of the powder in the vicinity of the corners in the cavity is lower than that in the central portion, which is a cause of strength reduction.
In particular, when a groove (recess) is formed near the end of the cavity, it becomes extremely difficult to fill the groove with the powder, which may deteriorate the quality of the molded product. Further, it is also known that the powder supply means is reciprocally moved in the horizontal direction so that the powder is distributed into the cavity when the powder is supplied. The particles are not always distributed uniformly, and for example, the powder may be biased toward the corner of the cavity. Further, in the conventional device, it takes a relatively long time to fill the device, and it is difficult to increase the productivity.

In view of the above situation, it is an object of the present invention to provide a powder molding press capable of uniformly and quickly filling powder in every corner of a cavity.

[0005]

According to a first aspect of the present invention, there is provided a powder molding press including a mold having a cavity therein, and a powder supplying means for supplying powder into the cavity of the mold. An upper die and a lower die for compressing the powder filled in the cavity, a vibrating means for vertically vibrating the lower die in the cavity of the mold frame, and a vibrating step as a filling step. And a filling control unit for supplying the powder into the cavity by the powder supply unit while vibrating the lower mold by the unit.

Here, the upper die and the lower die may have an uneven surface or may have a planar shape. Further, as the material of the powder, for example, various metals,
Examples thereof include ceramics, plastics, and composite materials.

Therefore, according to the powder molding press of the first aspect of the invention, in the filling step, the powder as the raw material is filled in the cavity of the mold frame. Specifically, when the filling control unit operates, the powder is supplied into the cavity by the powder supply unit while the lower mold is vibrated in the vertical direction by the vibrating unit. That is, the vibration of the lower mold promotes the fluidity of the supplied powder, and evenly fills every corner of the cavity.

A powder molding press according to a second aspect of the present invention is the powder molding press according to the first aspect, wherein the powder supply means includes a frame-shaped supply frame member and the powder on the supply frame member. A hopper for throwing in a body and a sliding means for sliding the supply frame material in a substantially horizontal direction between a throwing position corresponding to the hopper and a filling position corresponding to the cavity of the mold frame. The filling control means is configured to reciprocate the supply frame material in a substantially horizontal direction at the filling position when the powder is supplied.

Therefore, according to the powder molding press of the second aspect of the invention, in addition to the effect of the first aspect of the invention, since the feed frame material corresponds to the hopper at the feeding position, the powder is transferred from the hopper to the feed frame material. Is charged and a certain amount of powder is stored inside the supply frame material. After that, when the supply frame material slides from the charging position to the filling position by the sliding means, the supply frame material corresponds to the cavity of the mold frame and the powder can be supplied into the cavity. And at this time, the filling control means
Since the supply frame material is reciprocated substantially horizontally in the filling position, it is possible to supply the powder while changing the position of the supply frame material with respect to the cavity. As a result, the powder is distributed to the entire cavity. further,
The reciprocating motion of the supply frame material is transmitted to the filled powder, and the fluidity of the powder is further promoted.

A powder molding press according to a third aspect of the present invention is the powder molding press according to the first or second aspect, further comprising an underfill cylinder connected to the lower die, The means comprises a vibrating piston disposed in the housing of the cylinder and operating in the same direction with respect to the lifting piston of the cylinder.

Therefore, according to the powder molding press of the third aspect of the invention, in addition to the function of the first or second aspect of the invention, a well-known process called underfill is performed after the powder is filled. Be seen. This is to lower the position of the upper surface of the powder with respect to the upper end of the mold frame by slightly lowering the lower mold by a cylinder after filling the cavity with the powder. Thereby, even if the upper mold is inserted into the cavity in the molding step, the filled powder can be prevented from overflowing from the upper end of the mold frame. In the present invention including such an underfill cylinder, the vibration piston is integrally provided in the housing of the cylinder, and the lower die is vibrated by the reciprocating motion of the vibration piston.

A powder molding press according to a fourth aspect of the present invention is the powder molding press according to any one of the first to third aspects, wherein the vibrating means vibrates the lower mold as a molding step. While further, the compression molding control means for compressing the powder filled in the cavity by lowering the upper mold is further provided.

Therefore, according to the powder molding press of the invention of claim 4, in addition to the function of the invention of any one of claims 1 to 3, in the molding step, the upper die is lowered to
The powder is compressed between the upper mold and the lower mold. That is, the volume of the powder is contracted by applying pressure, and the molded product is formed by causing entanglement or adhesion between the powders. Then, the vibrating means is operated also in this molding step. That is, the powder is tightened while vibrating the lower mold. Therefore, the density of the powder in the molded product becomes more uniform.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A powder molding press which is an embodiment of the present invention will be described below with reference to FIGS. 1 is a front view showing the structure of a press body in the powder molding press, FIG. 2 is an enlarged cross-sectional view showing the structure of the main parts of the press body, and FIG. 3 is a powder supply device in the powder molding press. It is a side view which shows a structure, and FIG. 4 is a perspective view which shows a structure of the sliding member in a powder supply apparatus. Further, FIG. 5 is a block diagram showing a functional configuration of a control device in the powder molding press, and FIGS. 6 and 7 are explanatory diagrams showing an operation flow in the powder molding press.

As shown in FIGS. 1 and 3, the powder molding press 1 of this embodiment supplies a powder to the press body 2 and a press body 2 for molding a molded article by compressing the powder. The powder supply device 3 and a take-out device (not shown) for taking out and carrying out the molded product from the press body 2 are provided. Here, the powder supply device 3 corresponds to the powder supply means of the present invention.

The press body 2 comprises a base 4 and two columns 5
Is a vertically long device having an oil tank 6 on the upper side thereof, and a mold frame 7, an upper mold 8, and a lower mold 9 are provided at substantially central positions in the height direction. The mold frame 7 has two cavities C formed therein.
An upper die 8 and a lower die 9 are provided corresponding to the above.

The press main body 2 serves as a mechanism for moving the mold frame 7 up and down, and a frame guide 11 that supports the peripheral edge of the bottom surface of the mold frame 7, and a frame slide that is connected to the frame guide 11 via a connecting shaft 12. 13 and a mold frame cylinder 14 for moving the frame slide 13 up and down.

The press main body 2 is a mechanism for moving the upper die 8 up and down. The upper die slide 16 fixes the upper die 8 and is vertically slidable, and the upper die slide 16.
And an upper die cylinder 17 for sliding. Further, a pressurizing cylinder 19 operated by hydraulic pressure supplied from a pump PN (see FIG. 5) is connected to the center of the upper surface of the upper mold slide 16. And the upper mold slide 1
6 moves down by the operation of the upper mold cylinder 17 until the upper mold 8 is inserted into the cavity C, and then moves down by the operation of the pressurizing cylinder 19. That is,
The pressurizing cylinder 19 operates only during compression molding and compresses the powder with a large force. The hydraulic passage 19a of the pressurizing cylinder 19 communicates with the hydraulic tank 6 via the prefill valve 20, and the upper die slide 16 is connected to the upper die cylinder 17 by the upper die slide 16.
The prefill valve 20 is opened so that oil can be supplied from the hydraulic tank 6 to the hydraulic passage 19a so that the hydraulic passage 19a does not become a negative pressure state when descending. On the other hand, in a state where the pressurizing cylinder 19 is hydraulically actuated by the operation of the pump, the prefill valve 20 is closed to shut off the oil flow to the hydraulic tank 6.
The prefill valve 20 is open / close controlled by a pilot cylinder 21.

As shown in FIG. 2, the lower mold 9 comprises two molds, namely, a cylindrical first mold part 22 corresponding to the peripheral surface of the cavity C of the mold frame 7, and a first mold part 22. And a second mold part 24 having an operating cylinder 23 disposed therein. Here, the upper surface of the second mold portion 24 projects above the upper surface of the first mold portion 22. In other words, the upper surface of the first mold portion 22, the upper surface and the upper end outer peripheral surface of the second mold portion 24, the inner peripheral surface of the mold frame 7, and the bottom surface of the upper mold 8 droop the legs from the peripheral edge of the flat plate shape. It is possible to mold a molded product S having an inverted concave cross section. The operating cylinder 23
Are controlled by the counter balance valve 23a. The counter balance valve 23a is a kind of pressure control valve, and prevents the natural fall of the second mold part 24 due to its own weight by generating back pressure in a part of the circuit. When downward pressure is applied to the second die portion 24 when the powder P is compressed by the pressurizing cylinder 19, the second die portion 24 moves downward in proportion to the applied pressure. Therefore, the upper surface of the second mold portion 24 becomes low. In other words, the upper surface of the first die part 22 is relatively higher than the upper surface of the second die part 24. As a result, it becomes possible to compress the relatively thin flat plate portion SH and the relatively thick (long) leg portion SK of the molded product S at the same rate.

The lower die 9 is fixed to the upper surface of the lower die base member 25, and moves up and down or vibrates by the operation of the lower die cylinder 26. The lower die base member 25 is composed of a plurality of stacked plate materials and is held by a clamp cylinder 27. Also, the lower die base member 2
Reference numeral 5 is connected to the lower mold cylinder 26 via a connecting pin 28.

In the housing 29 of the lower die cylinder 26, two pistons, that is, an ascending / descending piston 30 for underfilling and a vibrating piston 31 for vibrating the lower die 9 are coaxially arranged. They are arranged in contact with each other. The strokes of the pistons 30 and 31 are not particularly limited, but in the present embodiment, the stroke of the lifting piston 30 arranged on the lower side is 5 m.
The stroke of the vibration piston 31 arranged on the upper side is set to 6 mm. When the raising / lowering piston 30 is raised, the vibration piston 31 also rises. Therefore, when the raising / lowering piston 30 is raised, the vibration piston 31
Has a stroke difference between the two pistons 30 and 31, that is, 1 mm in this case.

On the other hand, as shown in FIG. 3, the powder feeding device 3 is provided with a funnel-shaped hopper 32 and a sliding member 33 which is slidable in the horizontal direction. Specifically, the sliding member 33 is
As shown in FIG. 4, two support members 35 each having a bar-shaped guide rail 34 formed on the side surface, and these support members 3
It is composed of a supply frame member 37 and the like provided in a form sandwiched by 5 and having a through hole 36 in the center. Further, the powder supply device 3 includes a support plate 39 provided with a bearing 38 for slidably supporting the guide rail 34 of the sliding member 33.
And a supply cylinder 40 for sliding the sliding member 33. Then, by controlling the supply cylinder 40, the supply frame member 37 of the sliding member 33 can be slid between the loading position corresponding to the hopper 32 and the filling position corresponding to the cavity C. Here, the supply cylinder 40 corresponds to the sliding means of the present invention. In addition, below the powder supply device 3, the powder collecting member 4 for collecting the powder P overflowing from the through holes 36 of the supply frame material 37 at the time of charging.
1, a leg portion 42, and a roller 43 pivotally supported on the lower end of the leg portion 42.

The powder molding press 1 includes the mold frame cylinder 14, the upper mold cylinder 17, and the pressurizing cylinder 1 described above.
9, the lower die cylinder 26, the supply cylinder 40, etc., to operate based on a predetermined process,
A controller having a computer is provided. Also, it is equipped with a hydraulic control member such as a solenoid valve (including a solenoid proportional valve) for switching the hydraulic pressure applied to various cylinders.
Specifically, as shown in FIG. 5, the control device includes a filling control unit 51, an underfill control unit 52, and a compression molding control unit 53 as a functional configuration. The processing in these functional configurations will be described below with reference to FIGS.
The operation of the powder molding press 1 shown in FIG. It should be noted that FIGS. 6 and 7 show a simplified configuration of the powder molding press 1 for convenience.

The filling control means 51 fills the cavity C with the powder P, and includes four electromagnetic valves 45, 4
By controlling 6, 47, 48, the supply cylinder 40, the mold frame cylinder 14, and the lower mold cylinder 26.
To operate. That is, from the initial state shown in FIG. 6 (a), first, the mold frame 7 is raised to move the cavity C
And the supply frame member 37 is slid to the filling position (see FIG. 6B). Thereby, the supply frame member 37
Therefore, the powder P can be sequentially supplied into the cavity C. Particularly, in the present invention, when the powder P is supplied, the lower mold 9 is vibrated in the vertical direction and the supply frame member 37 is reciprocated at the filling position. As a result, the powder P filled in the cavity C is vibrated, and the fluidity is enhanced. Here, the state shown in FIG. 6B corresponds to the filling step of the present invention. After the powder P is filled in the cavity C, the vibration of the lower mold 9 is stopped and the supply frame member 37 is returned to the loading position, as shown in FIG. 6C. As a result, the powder P is put into the empty supply frame member 37 from the hopper 32 again.

Subsequently, the underfill control means 52
By controlling the solenoid valve 47, the lifting piston 30
To operate. That is, as shown in FIG. 7D and FIG. 2 (particularly, the right half of the drawing), the lower die 9 is slightly lowered (for example, 5 mm) by the lifting piston 30. As a result, the upper surface of the powder P filled in the cavity C is lowered. That is, even if the upper mold 8 is inserted into the mold frame 7, the powder P
Will not overflow from the upper surface of the mold frame 7. The lower mold 9 is not vibrated when performing underfill.

Next, the compression molding control means 53 controls the solenoid valve 4
The upper die cylinder 17 and the pressurizing cylinder 19 are operated by controlling the pump 9 and the pump PN. That is, as shown in FIG. 7E, when the upper die cylinder 17 lowers the upper die 8 and the upper die 8 comes into contact with the upper surface of the powder P (the upper die 8 descends to the abutting position). When this is detected by a position sensor (not shown)), the pressurizing cylinder 19 urges the upper mold 8 downward. In addition,
When the pressurizing cylinder 19 is operated, the pilot cylinder 21 is operated by controlling the solenoid valve 50, and the prefill valve 20 is closed. Further, the compression molding control means 53 controls the electromagnetic valve 48 to operate the vibration piston 31 of the lower mold cylinder 26 when operating the pressurizing cylinder 19, that is, when compressing the powder P.
This allows the lower mold 9 to be compressed while vibrating. Since the pressure of the vibration piston 31 is much smaller than the pressure of the pressurizing cylinder 19, the lower mold 9
The vibration of is controlled by the upper mold 8. In other words, when the powder P starts to be compressed, it vibrates with a predetermined amplitude, but as it is compressed, the amplitude gradually decreases, and finally does not vibrate. Here, the state shown in FIG. 7E corresponds to the molding step of the present invention.

After being compression-molded, as shown in FIG. 7 (f), the upper mold 8 is moved up by the operation of the upper mold cylinder 17, and the mold frame 7 is moved by the operation of the mold frame cylinder 14. Goes down. As a result, the compression-molded product S is projected from the upper surface of the mold frame 7, and can be taken out by the take-out device.

As described above, in the above-mentioned powder molding press 1, by supplying the powder P while vibrating the lower die 9, the fluidity of the supplied powder P is promoted and the cavity C
The powder P can be uniformly filled up to every corner inside. Therefore, the density of the powder P in the molded product S becomes uniform,
It is possible to suppress a decrease in strength at the end. In particular, the reciprocating movement of the supply frame member 37 exerts horizontal vibration, and the powder P
Can be complicated and the fluidity of the powder P can be further promoted. Therefore, the quality of the molded product S can be improved, and since the filling can be performed relatively quickly, the productivity of the molded product S can be improved.

Further, in the above-mentioned powder molding press 1, since the ascending / descending piston 30 and the vibrating piston 31 are provided in the one housing 29, the manufacturing cost can be reduced and the overall size can be reduced. . In other words, when the two pistons 30 and 31 are provided in different housings, the vibration piston 31 must be arranged on the lower die base member 25 that moves up and down by the lifting piston 30, which makes the structure extremely complicated. However, the integration as in the present embodiment simplifies the overall structure and facilitates manufacturing.

Further, in the powder molding press 1 described above, in the molding process, the density of the powder P in the molded product S can be made more uniform by compressing the powder P while vibrating the lower mold 9. The quality of the product S can be further improved.

Although the present invention has been described above with reference to the preferred embodiments, the present invention is not limited to these embodiments, and as shown below, within the scope not departing from the gist of the present invention. Various improvements and design changes are possible.

For example, in the above-described embodiment, the case where the upper die 8 has a planar shape and the lower die 9 has a concavo-convex shape has been described, but the upper die and the lower die both have a planar shape. The same can be applied to a die or a press body equipped with a die having an uneven surface.

In the above embodiment, the lower mold 9 is vibrated even during compression molding. However, when the powder P can be surely made uniform in the filling step, or even when vibrated during compression, the fluidity of the lower mold 9 is reduced. If the material cannot be improved, it is not necessary to vibrate during compression molding.

Further, in the above-described embodiment, the cavity C is formed by raising the mold frame 7 with respect to the lower mold 9, but conversely, the mold C is formed with respect to the mold frame 7. The cavity C may be formed by lowering the lower mold 9. Further, although the vibrating means using the vibrating piston 31 is shown, the vibrating means may use an electromagnetic valve, a motor or the like to generate the vibration.

[0035]

As described above, in the powder molding press of the first aspect of the invention, by supplying the powder while vibrating the lower die, the fluidity of the supplied powder is promoted and the inside of the cavity is accelerated. It is possible to uniformly fill the powder in every corner. Therefore, the density of the powder in the molded product becomes uniform, and the decrease in strength at the end can be suppressed. That is, the quality of the molded product can be improved. In addition, since the filling can be performed relatively quickly, the productivity of the molded product can be improved and the manufacturing cost can be reduced.

According to the powder molding press of the second aspect of the invention, in addition to the effect of the first aspect of the invention, the powder is evenly distributed by the reciprocating movement of the feed frame material, and the horizontal vibration and the vertical direction are applied. The vibration of the powder can be complicated and the fluidity of the powder can be further promoted by the combination with the vibration of the powder.
As a result, the quality of the molded product can be significantly improved and the time required for filling can be further shortened.

According to the powder molding press of the third aspect of the present invention, in addition to the effect of the first or second aspect of the invention, the lifting piston and the vibration piston are arranged in one housing. The manufacturing cost is lower and the size can be reduced as a whole, as compared with the case where different cylinders are provided.

According to the powder molding press of the invention of claim 4, in addition to the effect of any one of claims 1 to 3, in the molding step, the powder is compressed while vibrating the lower mold. Thereby, the density of the powder in the molded product can be made more uniform, and the quality of the molded product can be further improved.

[Brief description of drawings]

FIG. 1 is a front view showing a configuration of a press body in a powder molding press which is an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing the configuration of the main part of the press body.

FIG. 3 is a side view showing a configuration of a powder supply device in the powder molding press.

FIG. 4 is a perspective view showing a configuration of a sliding member in the powder supply device.

FIG. 5 is a block diagram showing a functional configuration of a control device of the powder molding press.

FIG. 6 is an explanatory diagram showing a flow of operations in the powder molding press.

FIG. 7 is an explanatory diagram showing a flow of operations in the powder molding press.

[Explanation of symbols]

1 Powder molding press 3 Powder supply device (powder supply means) 7 Mold frame 8 Upper mold 9 Lower mold 14 Cylinder for mold frame 26 Lower mold cylinder (underfill cylinder) 29 housing 30 Lifting piston 31 Vibration piston 37 Supply frame material 40 Supply cylinder (sliding means) 51 filling control means 53 Compression molding control means P powder C cavity

Claims (4)

[Claims] 1. A mold frame having a cavity inside, a powder supply means for supplying powder into the cavity of the mold frame, and an upper mold for compressing the powder filled in the cavity. And a lower die, a vibrating means for vertically vibrating the lower die in the cavity of the mold frame, and as a filling step, the vibrating means vibrates the lower die while the powder feeding means A powder molding press comprising: a filling control means for supplying the powder into the cavity. 2. The powder supply means, a frame-shaped supply frame member, a hopper for charging the powder into the supply frame member, a position for charging the supply frame member corresponding to the hopper, and Sliding means for sliding in a substantially horizontal direction between filling positions corresponding to the cavities of the mold frame, wherein the filling control means fills the supply frame material when supplying the powder. The powder molding press according to claim 1, wherein the powder molding press is reciprocated in a substantially horizontal direction at a position. 3. An underfill cylinder connected to the lower die is further provided, and the vibrating means is disposed in a housing of the cylinder and operates in the same direction with respect to a lifting piston of the cylinder. The powder molding press according to claim 1 or 2, comprising a vibration piston. 4. The molding step further comprises compression molding control means for compressing the powder filled in the cavity by lowering the upper die while vibrating the lower die by the vibrating means. The powder molding press according to any one of claims 1 to 3.