JPH1085992A - Powder supplying device of powder compacting press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently heat a raw material of powder passing through the inside of a supplying tube by forming the inside face of the supplying tube installed with a heating means on the circumferential wall part into a rugged shape. SOLUTION: When a raw material of powder is heated in a heating tube 14, because the inside face of the supplying tube 14 is made into a rugged shape, the inside face area is large and the contact area of the inside face of the supplying tube body 41 and the area material of powder is made large, heat is transmitted well from a heater 30 to the raw material of powder of passing inside the supplying tube body 41. Further, because a recessing part 43 and a projecting part 44 on the inside face of the supplying tube body 51 are made in a contiguous shape like along the axial direction of the supplying tube 14, the raw material of powder is guided along the recessing part 43 and the projecting part 44 and it is passed smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder supply device for a powder molding press, and more particularly to a supply pipe for supplying raw material powder from a raw material container to a feeder.

[0002]

SUMMARY OF THE INVENTION In powder metallurgy,
A raw material powder mainly composed of a metal such as iron is compressed by a powder molding press to form a green compact, and the green compact is heated and sintered in a sintering furnace. During the molding of the green compact, if the raw material powder is heated, even if pressed at the same pressure, the density and strength of the green compact can be increased, and the breakage of the green compact can be prevented. There are advantages such as enabling machining. Therefore, conventionally, as described in, for example, JP-A-8-41501, a powder molding method in which a heating means is provided in a powder feeding device of a powder molding press and a raw material powder is heated before pressing is performed. I have.

As described in the above publication, in a powder feeding apparatus, generally, a raw material powder is supplied from a hopper storing the raw material powder into a feeder moving on a molding die. The raw material powder is filled into the molding die from this feeder. For example, a flexible feeder hose is used as a supply pipe for supplying raw material powder from the hopper to the feeder. When a feeder hose is used in a powder feeder that heats raw material powder before pressurization, a heating wire is wound around an outer peripheral side of a hose body made of a soft synthetic resin, and furthermore, a feeder hose is formed by covering the outside with a heat insulating material. ing. And conventionally, the inner surface of the hose body is smooth,
The cross section was formed in a substantially circular shape.

However, if the inner surface of the hose body is smooth and its cross section is substantially circular, the area of the inner surface of the hose body is small, so that the contact area between the inner surface and the raw material powder is small. There is a problem that the raw material powder passing through the body cannot be efficiently heated.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a powder feeding apparatus for a powder molding press capable of efficiently heating a raw material powder passing through a supply pipe.

[0006]

According to a first aspect of the present invention, there is provided a powder-feeding apparatus for a powder-forming press, wherein the powder-feeding apparatus is provided with a raw material container for storing raw material powder, A feeder for filling the raw material powder into the molding die,
A supply pipe for supplying the raw material powder from the raw material container to the feeder, and a heating means provided on a peripheral wall of the supply pipe are provided, and the inner surface of the supply pipe is formed in an uneven shape.

At the time of molding, the raw material powder stored in the raw material container is supplied to a feeder through a supply pipe, and the feeder moves on a molding die, and the raw material powder is placed in the molding die. Supplied. The raw material powder is heated by the heating means provided on the peripheral wall of the supply pipe while passing through the supply pipe. At this time, since the inner surface of the supply pipe is uneven, and the area of the inner surface of the supply pipe is large, the contact area between the inner surface and the raw material powder is large. Heat is transmitted to.

According to a second aspect of the present invention, in the powder feeding device for a powder molding press according to the first aspect of the present invention, the irregularities on the inner surface of the supply pipe are formed to be continuous along the axial direction of the supply pipe. .

Accordingly, the raw material powder is guided along the uneven portion on the inner surface of the supply pipe, and smoothly passes through the supply pipe.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a powder feeding device for a powder molding press according to the present invention will be described below with reference to FIGS. In FIG. 1, reference numeral 1 denotes a press body, on which a molding die 2 is provided. The molding die 2 has a die 3, a lower punch 4, and an upper punch 5, and forms a green compact by pressing the raw material powder by the lower punch 4 and the upper punch 5 in the die 3. It is.

A powder feeding device 11 includes a raw material container 12 for storing raw material powder, a feeder 13 for linearly reciprocating on a horizontal upper surface of the die 3 and filling the die 3 with raw material powder,
And a supply pipe 14 for supplying raw material powder from the raw material container 12 to the feeder 13. The raw material container 12 has an upper hopper
16, a heat exchange section 17 as a heating means provided below the upper hopper 16, and a lower hopper 18 provided below the heat exchange section 17. The upper hopper
16 is a horizontal support shaft on an arm 19 provided on the press body 1
It is swingably supported by 20. The axial direction of the support shaft 20 is a direction orthogonal to the moving direction of the feeder 13. The heat exchange section 17 passes the oil heated by the oil heater 21 and gives the heat of the oil to the raw material powder. In the heat exchange section 17, the oil passage and the raw material passage are separated from each other. Also,
The feeder 13 is driven by a motor via a feeder cam or a feeder lever 22, for example. Further, the supply pipe 14 is a flexible hose, one end of which is connected to the outlet 23 at the lower end of the lower hopper 18, and the other end of which is connected to the feeder 13.

As shown in FIG. 3, the die 3 and the upper punch 5 of the molding die 2 and the feeder 13 and the supply pipe 14 of the powder supply device 11 are provided with electric power as heating means for heating the raw material powder. Heaters 27, 28, 29, 30 and temperature sensor 3
1, 32, 33, and 34 are provided, respectively. These heaters 27, 28, 29, 30 are controlled by a heater controller 35 in accordance with the temperatures detected by the temperature sensors 31, 32, 33, 34.

As shown in FIG. 2, the supply pipe 14 has a heater 30 made of a heating wire wound around an outer peripheral surface of a supply pipe main body 41 made of a soft synthetic resin, and further covers these heaters 30 from outside. A heat insulating material 42 made of silicone rubber or the like is provided. A plurality of concave portions 43 and convex portions 44 are formed on the inner surface of the supply pipe main body 41.
The concave portion 43 and the convex portion 44 are formed as continuous wide grooves or ridges extending along the axial direction of the supply pipe 14 and have a shape parallel to the axial direction.

Next, the operation of the above configuration will be described. During molding, the raw material powder in the upper hopper 16 is supplied into the feeder 13 through the heat exchange unit 17, the lower hopper 18, and the supply pipe 14. Then, in a state where the upper punch 5 is lifted and comes out of the die 3, the feeder 13 moves above the hole of the die 3 as shown by a chain line in FIG. The raw material powder is filled. Then, as shown by the solid line in FIG. 1, after the feeder 13 is retracted, the descending upper punch 5 is fitted into the die 3, and the raw powder is compressed by the lower punch 4 and the upper punch 5 in the die 3. Then, a green compact is formed. The formed green compact is extracted from the die 3 by the lower punch 4.

At the time of such molding, the raw material powder is first heated to about 135 ° C. by oil when passing through the heat exchange section 17 in the raw material container 12. Next, the raw powder is heated by the heater 30 of the supply pipe 14 when passing through the supply pipe 14. This prevents the temperature of the raw material powder from dropping while passing through the supply pipe 14. The raw material powder is also heated in the feeder 13 by the heater 29 provided in the feeder 13. Further, the raw material powder is also supplied to the die 3 and the upper punch 5 in the die 3.
Are heated by the heaters 27 and 28 provided in the heater. Thus, the temperature of the raw material powder when pressurized becomes about 150 ° C. Thereby, the density and strength of the formed green compact can be increased.

In particular, when the raw material powder is heated by the supply pipe 14, the inner surface of the supply pipe body 41 is uneven, and the area of the inner surface of the supply pipe body 41 is large. The contact area between the inner surface and the raw material powder is large, and heat is favorably transmitted from the heater 30 provided on the outer peripheral side of the supply pipe main body 41 to the raw material powder passing through the supply pipe main body 41. Therefore, in the supply pipe 14, the raw material powder can be efficiently heated.

Further, since the concave portion 43 and the convex portion 44 on the inner surface of the supply tube main body 41 are formed to be continuous along the axial direction of the supply tube 14, the raw material powder is guided along the concave portion 43 and the convex portion 44. , Smoothly pass through the supply pipe main body 41. Thus, despite the fact that the inner surface of the supply pipe main body 41 was formed in an uneven shape,
A decrease in the fluidity of the raw material powder in the supply pipe main body 41 can be prevented.

Next, a second embodiment of the powder supply device for a powder molding press according to the present invention will be described with reference to FIGS. The same parts as those in the first embodiment described above are denoted by the same reference numerals, and description thereof will be omitted. In the second embodiment, the supply pipe 51 for supplying the raw material powder from the raw material container 12 to the feeder 13 mainly includes a metal material.
This metal material is not flexible as a material itself, but in order to allow the feeder 13 to move,
A bendable joint portion 52 is provided at three places in the middle of 51.
The supply pipe 51 includes a plurality of supply pipe main bodies formed of a metal pipe.
53 is connected at a joint portion 52. The heater 30 made of a heating wire is wound around the outer peripheral surface of each supply pipe main body 53, and a heat insulating material 42 covers the heater 30 from outside. The material of the supply pipe main body 53 is preferably a metal having excellent thermal conductivity such as copper, a copper alloy or stainless steel. Further, the joint portion 52 is configured such that a fitting portion 54 and a fitting seat portion 55 formed at an end of an adjacent supply pipe main body 53 are rotatably fitted to each other. That is, the outer surface of the fitting portion 54 that forms a spherical or cylindrical surface and the inner surface of the fitting seat 55 that forms a spherical or cylindrical surface are slidably fitted. When the sliding surface of the fitting portion 54 and the fitting seat portion 55 is a cylindrical surface,
Its central axis, that is, the rotation axis, is horizontal and feeder 13
In the direction perpendicular to the moving direction. And the supply pipe body
On the inner surface of 53, a plurality of concave portions 56 and convex portions 57 are formed. The concave portions 56 and the convex portions 57 are wide bottom grooves or ridges that are continuous along the axial direction of the supply pipe 51, and have a shape parallel to the axial direction.

When the raw material powder is heated by the supply pipe 51, the supply pipe main body 53 is made of metal having excellent heat conductivity, in combination with the fact that the inner surface of the supply pipe main body 53 is uneven. As a result, heat is favorably transmitted from the heater 30 provided on the outer peripheral side of the supply pipe main body 53 to the raw material powder passing through the supply pipe main body 53. Therefore, in the supply pipe 51, the raw material powder can be heated more efficiently.

The metal supply pipe main body 53 itself is not flexible, but as shown by solid and chain lines in FIG. In the portion 52, the feed pipe main body 53 is rotated and bent to allow the feeder 13 to move linearly on the horizontal upper surface of the die 3. In other words, the provision of the bendable joint 52 in the supply pipe 51 allows the supply pipe 51 to be made of metal in the powder feeding device 11 in which the feeder 13 moves linearly. is there.

In order to allow the feeder 13 to move linearly, three or more joints 52 are required. However, if the raw material container 12 is swingably supported by the support shaft 20 as in the powder supply device 11 of the above-described embodiment, the support shaft 20 can also be used as one joint, so that the supply pipe 51 May be provided with only two joint portions 52.

Further, the present invention is not limited to the above embodiment, and various modifications can be made. For example, the concave and convex shapes on the inner surfaces of the supply pipe main bodies 41 and 53 are not limited to those in the above-described embodiment, and may have a shape whose cross section substantially forms a sine curve. The concave and convex portions on the inner surface of the supply pipe main body need not be parallel to the axial direction of the supply pipe main body, and may be spirally inclined. further,
The heating means for heating the raw material powder is not limited to a heater using a heating wire or heat exchange with oil as in the above-described embodiment, but may be a heater using high-frequency heating.

[0023]

According to the powder supply device of the present invention, since the inner surface of the supply pipe provided with the heating means on the peripheral wall portion is formed in an uneven shape, the raw material powder passing through the supply pipe is formed. It can be heated efficiently.

According to the powder feeding device of the powder molding press of the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, the irregularities on the inner surface of the supply pipe are continuously formed along the axial direction of the supply pipe. Therefore, it is possible to prevent a decrease in the fluidity of the raw material powder in the supply pipe despite the fact that the inner surface of the supply pipe is formed in an uneven shape.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a first embodiment of a powder feeding device for a powder molding press according to the present invention.

2 (a) is a cross-sectional view showing the supply pipe, and FIG.
It is a longitudinal cross-sectional view.

FIG. 3 is a block diagram of the same.

FIG. 4 is a schematic side view showing a second embodiment of the powder supplying device of the powder molding press according to the present invention.

FIG. 5 is a sectional view showing a joint portion of the supply pipe.

[Explanation of symbols]

 2 Molding die 11 Powder supply device 12 Raw material container 13 Feeder 14 Supply pipe 30 Electric heater (heating means) 43 Concave section 44 Convex section 51 Supply pipe 56 Concave section 57 Convex section

Claims (2)

[Claims] 1. A raw material container for storing raw material powder, a feeder which moves on a molding die and fills the raw material powder into the molding die, and a supply for supplying the raw material powder from the raw material container to the feeder. A powder feeding device for a powder molding press, comprising: a pipe; and heating means provided on a peripheral wall portion of the supply pipe, wherein an inner surface of the supply pipe is formed in an uneven shape. 2. The powder feeding apparatus for a powder molding press according to claim 1, wherein the uneven portion on the inner surface of the supply pipe is formed to be continuous along the axial direction of the supply pipe.