JP2001316704A - Extruded sintered compact - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extruded sintered compact with a high bonding strength without applying an excessive load on an extruder and a die, by using an extrusion device having a pin forming laminar spaces connected with each other on a curved surface in the die. SOLUTION: When a kneaded body of a metal powder and a binder is extruded toward the die having the pin forming the laminar spaces communicated with each other on the curved surface inside thereof, the kneaded body is passed through a kneaded body flow passage provided in the pin, and compressed, sheared and joined by the taper of the die. In addition, a molding having laminar spaces communicated with each other on the curved surface formed therein is extruded by the pin. This molding is sintered to obtain the extrusion sintered compact.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extruded sintered body obtained by sintering a metal or an alloy in which layered voids which are communicated with curved surfaces by extrusion are formed.

[0002]

2. Description of the Related Art In the field of materials such as metal materials, cemented carbides and ceramics, so-called hollow products having a hole in the material are widely used. Among hollow products, hollow products such as irregularly shaped honeycomb structures applied to catalyst carriers and the like are porous, and are usually manufactured by welding plate materials or pipe materials. In recent years, when manufacturing by a welding structure, the cost becomes high. Therefore, Japanese Patent Application Laid-Open No. 8-239701 proposes to obtain a honeycomb formed body by an extrusion sintering method.

[0003]

The above-mentioned JP-A-8-23
The honeycomb formed body disclosed in Japanese Patent No. 9701 has a rectangular hole. However, such a rectangular hole has a problem that a sufficient contact area cannot be obtained when the rectangular hole is used, for example, as a catalyst carrier. The present invention has been made in view of the above problems, and has as its object to provide a molded sintered body having continuous curved voids formed in layers.

[0004]

Means for Solving the Problems The present inventor has found that a layered space can be formed by extrusion by arranging layered pins, and has reached the present invention. That is, the present invention is an extruded sintered body having a layered void communicating with a curved surface. It is preferable that the voids of the extruded sintered body of the present invention have three or more layers, and the voids have a curved surface substantially along the curved surface of the adjacent voids.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the extruded sintered body of the present invention, the curved surface of the void increases the contact area of the fluid as compared with a linear one. For example, when the sintered body is used as an exhaust gas filter of an automobile, the exhaust gas adsorption rate Can be improved.

Further, in the extruded sintered body of the present invention,
It is preferable to form three or more voids since the contact area of the fluid can be further improved. Furthermore, it is preferable to have a curved surface substantially along the gap curved surface that is substantially adjacent to the gap because the gap between the gaps can be reduced. For example, when used in an exhaust gas filter, the resistance of gas flow is reduced, and pressure loss can be reduced. Further, when the core of the reluctance motor is used for forming a magnetic path, the flow of magnetic flux can be made smooth, and it can be used for a motor for high-speed rotation.

[0007]

FIG. 2 is a view showing one embodiment of an extrusion molding apparatus for obtaining an extrusion molded sintered body of the present invention having three layers of voids connected by curved surfaces shown in FIG. In the present embodiment, an extruder 2 including a cylinder 2a and a screw 2b was used as a kneading body supply device. First extruded sintered body 1 shown in FIG.
A first layer forming pin 3 and a second layer forming pin 4 having a taper post 7 having a kneaded body passage hole 8 for forming the layer hole 1a, the second layer hole 1b and the third layer hole 1c. The third layer forming pins 5 are assembled in the order shown in FIG.

When the extruder 2 is driven by the above-described apparatus to extrude a kneaded body (not shown), the kneaded body passes through the kneaded body flow passage holes of each pin and is simultaneously driven by the inner diameter taper 6a of the die 6. While being compressed and sheared, it is sent to the bearing part 6b of the die 6, and the respective layers form a layered void communicating with the curved surface. By extruding the molded body to a predetermined length and cutting it, a molded body of the extruded sintered body 1 of the present invention before sintering as shown in FIG. 1 is obtained. Thereafter, after drying the above-mentioned molded body, binder removal and sintering are performed to obtain an extruded sintered body of the present invention shown in FIG. The above kneaded material is prepared, for example, by adding methylcellulose (SM4000 and 60sh4000 under commercial names) to stainless powder having an average particle size of 10 μm.
Is mixed), glycerin, stearic acid emulsion and water are added, followed by kneading with a kneader kneader for 15 minutes. When each amount is shown by volume%, methylcellulose 5% (SM4000 is 3.5% + 60sh)
4000 is 1.5%), glycerin 1%, stearic acid emulsion 1%, water 10%, and the balance is stainless steel powder.

Further, the extruded sintered body of the present invention having a cross-sectional shape having a layered void communicating with a curved surface as shown in FIG. 5 also has the shape of the pin tip shown in FIG. The kneaded body is extruded by using the extruder, and a molded body is obtained. After drying the molded body, binder removal and sintering are performed to obtain an extruded sintered body.

FIG. 5 shows another example of the extruded sintered body of the present invention. The extruded sintered bodies 9, 10 and 11 have a large surface area of the voids and can be applied as a carrier of an exhaust gas filter of an automobile. The extruded sintered bodies 10 are a four-pole reluctance motor rotor. It can also be used as a negative shape.

The above-described layered voids communicating with each other on the curved surface of the extruded sintered body are straight in the longitudinal direction.
By performing extrusion molding using a die provided with several helical grooves in the bearing portion 6b of the die 6 shown in (1), it is possible to obtain a layered void that is twisted in the longitudinal direction and communicates with a curved surface. Further, even when extrusion molding is performed using an extrusion molding apparatus provided with a mechanism for rotating a pin, it is possible to obtain a layered void that is twisted in the longitudinal direction and communicates with a curved surface. Of course, such longitudinally twisted shapes are also within the scope of the present invention.

In this embodiment, when the kneaded body is extruded from an extruder, a multilayer hole is formed by a plurality of pins contained in a die having an inner diameter taper portion. Since the tape has the same tape as the inner diameter tape, the flow of the kneaded body is smooth. In addition, since the taper section has a kneaded body passage hole, the flow of the kneaded body to the pin for forming the next layer is smooth. Furthermore, since the kneaded body is compressed and sheared by the inner diameter tape of the die, the joining force is increased, the strength of the molded body is increased, and the prevention of cracks and the like can be greatly improved.

[0013]

As described above, according to the present invention, it is possible to obtain an extruded sintered body having layered voids communicating with each other on a curved surface, which is suitable for a catalyst carrier, a core of a reluctance motor, an exhaust gas filter, and the like. It is possible to provide a compact extruded sintered body.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an extruded sintered body of the present invention.

FIG. 2 is a schematic diagram showing an example of a pin and a die which are main parts of an extrusion molding apparatus for obtaining an extrusion molded body of the present invention.

FIG. 3 is a cross-sectional view of an extruded sintered body 3 of the present invention,
It is a schematic diagram explaining the assembly of the pin which shape | molds the molded object which has the space | gap of a layer.

FIG. 4 shows three extruded sinters of the present invention, which are communicated with each other on a curved surface.
It is the schematic diagram which looked at the state which assembled the pin which shape | molds the molded object which has the space | gap of a layer from the front.

FIG. 5 is a schematic view showing another cross-sectional shape of the extrusion-molded sintered body of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Extruded sintered compact, 1a 1st layer hole, 1b 2nd layer hole, 1c 3rd layer hole, 2 extruders, 3rd layer forming pin, 4th layer forming pin, 5th layer Forming pin, 6
Die, 6a taper part, 6b bearing part, 7 pin support, 8 kneaded body flow path, 9 extruded sintered body, 10 extruded sintered body, 11 extruded sintered body

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Claims (3)

[Claims] 1. An extruded sintered body characterized by having a layered void communicating with a curved surface. 2. The extruded sintered body according to claim 1, wherein three or more voids are formed. 3. The extruded sintered body according to claim 1, wherein the void has a curved surface substantially along the curved surface of the void.