JPS5932108A - Manufacture of electromagnetic iron core - Google Patents

Abstract

PURPOSE:To easily obtain electromagnetic iron core in different shapes by mixing iron powder and plastic in the specific rate under normal temperature, plasticizing plastic by kneading it with kneading injection molding machine and by directly injecting the plastic into the die through the injection molding machine. CONSTITUTION:A raw material inserting hole 3 and an air exhausting hole 13 are provided to a cylinder 2 of which external side is surrounded by a heater 15, a screw 16 which is rotated by driving system 18 and is provided with a groove 12 which is lasted in the axial direction is inserted into the cylinder 2 and an injection nozzle 5 is provided at the end of cylinder 2. On the entrance hole 3, the fixed amount feeders 1A and 1B which supply different kinds of materials are provided. Thus, the iron powder of 91-93% and plastic of 9-7% are accommodated therein. Moreover, the cylinder 2 is divided, from the side of entrance 3, into the feed preheating part I , plasticizing and kneading zone II, air exhausting zone III, measuring zone IV. Of these zones, the zones II and IIIare directioned to the advancing direction and diameter of screw 6 is gradually reduced. Thereby, the raw material pushed out from the nozzle 5 is injected into the metal die.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inexpensive manufacturing method for products made of hardened iron powder, such as electromagnetic cores.

Conventionally, electromagnetic iron cores have been manufactured by punching iron plates into a predetermined shape using a press and joining them with rivets, or by machine cutting a steel bar into a predetermined shape.
It was very time consuming to manufacture. Alternatively, there is a method in which iron powder is kneaded with a binder, pelletized, pressed, machined into a predetermined shape, and then sintered, but this method also requires complicated processes and high production costs.

The present invention was made to solve these conventional drawbacks, and by employing an injection molding method, it can be manufactured very easily. That is, this invention uses 91 to 93% iron powder and 9 to 7% plastic.
The weight ratio of the plastic is mixed at room temperature, the mixture is kneaded in a cross-wire injection molding machine to plasticize the plastic, and the plasticized state is injected into a mold through an injection molding machine to mold it into a predetermined shape. This is what I did.

The above components cannot be molded by conventional injection molding methods. This is because, according to the conventional injection molding method, a mixture of iron powder and plastic is kneaded in a mixing machine to form pellets, and then the pellets are fed to an injection molding machine where they are plasticized and fed into the mold from the injection section. However, in this first case, a large frictional force is generated between the screw and cylinder during transport until the pellets supplied into the injection molding machine are plasticized, causing damage to the screw and cylinder. It is from. Therefore, in order to perform the q-1 extrusion molding method using the conventional method, the content of plastic must be increased, and it was impossible to apply the conventional method to mixtures with iron content exceeding 90%. .

Therefore, in this invention, a kneading and injection molding machine is used in which a kneading machine and an injection molding machine are integrated, and the material that is kneaded and plasticized in the mixing section is transferred to the injection molding machine in a plasticized state for injection molding. . In this way, the process of transporting the solidified pellets through the injection molding machine to plasticize them is eliminated, and the problem of large frictional forces that occur in this process is also eliminated. The mixture can be injection molded.

Next, a kneading injection molding machine for carrying out the method of the present invention will be explained with reference to the drawings. In Figure 1, 2 is a cylinder, 3
is an input port, 6 is a screw, and inputs 1-13 are quantitative tweeters LA and IB for supplying different materials.
are connected. Inside the cylinder, a feed preheating zone, a plasticization kneading zone, a degassing zone, and a metering zone are formed sequentially from the input port side, and an injection nozzle is located at the tip.
are connected. 18T/i screw 6 drive device,
13 is an exhalation port, and 15 is a heater.

In the plasticization kneading zone, as shown in Fig. 2, six flights, or kneading blades 7, are formed on the screw 6, and these mixing blades have an angle approximating the twist angle of the rotor blade of an intensive mixer or Pampari mixer. It is formed in a continuous spiral. The mixing blade has a front wall 8 in the rotational direction R of the screw that is almost perpendicular to the rotational direction,
Further, tu L 6 is formed between the blades so that the screw diameter gradually decreases toward the rear in the rotational direction. On the other hand, a plurality of axially continuous grooves 12 are formed on the corresponding cylinder inner surface 14. These 12 grooves are continuous up to the feed preheating section 1, and in the feed preheating section 1, these grooves serve to assist in the transfer of the material. The front wall 17I/'i of the screw 12 in the direction of rotation is formed so as to correspond to the groove 16 of the screw so as to be substantially orthogonal to the direction of rotation. This shape is formed from the plasticization kneading zone ■ to the degassing zone III,
From the kneading zone ■ to the deaeration zone III, the land at the tip of the kneading grade is narrowed by 10 places, and the groove 11 in the deaeration zone is made larger than the groove 16 in the mixing zone, and the groove 12 of the cylinder is made narrower in the deaeration zone. Not allowed to form. The depth H and width B' of the steamer 12 are appropriately set so that the compression of the material and the turning operation of the material due to the flow of the compression occur.

Next, the operation of this device will be explained. In the cylinder 2, which is maintained at a temperature necessary to plasticize the resin by the heater 15, plastic is fed from the quantitative feeder IA, and iron powder is fed from the constant current tweeter IB at a constant mixing ratio.
The mixture is then fed as a mixture, and then sent to the preheated kneading zone (2) in the preheating zone (2) by rotation of the screw 6.

In the crosstalk zone (2), the rotation of the screw 6 causes the grooves 16 to alternately face the inner wall 14 of the cylinder and the grooves 12, so that the shearing process S and the compression process P are performed as shown in FIG. They are formed alternately along the rotation direction R. That is, as the rotation progresses from the position where the groove 16 of the screw and the groove 12 of the cylinder face each other as shown in the figure, the gap between the two grooves narrows and the walls 8 and 17 at the front in the direction of rotation approach each other. is compressed and subjected to a cutting action by the flow of compression, and a portion is sequentially sent between the land 10 of the plate and the inner wall 14 of the cylinder, where it is subjected to a shearing action. By repeating these compression, cutting, and shearing actions, the material is sufficiently mixed, and is then degassed while passing through the degassing zone, and flows from the edge into the mold (not shown). be ejected.

In addition, in the above operation, when molding was performed with the mixing ratio of iron powder and plastic and the temperature and pressure conditions set as shown in Table 1, good molded products were obtained for all samples 1 to 3. Moreover, no damage to screws etc. occurred. Furthermore, according to this method, the shape of the molded product can be freely set by selecting the mold, and there is no need for machining of the molded product, so there is an advantage that even products with complex shapes can be manufactured easily.

Table 1 As explained above, this invention manufactures a mixture of plastic and iron powder, such as an electromagnetic core, by injection molding, making it extremely easy to manufacture products of various shapes. It is possible.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an example of an apparatus for carrying out this invention, Fig. 2 is a sectional view taken along the line A-A, Fig. 3 is a sectional view taken along the line B-B, and Fig. 4 1-1: Kneading. It is an explanatory view of a mechanism. 2... Cylinder, 6... Screw, 7... Mixing blade, 11... Screw groove, 12... Cylinder groove. Patent applicant Yasushi Yamaoka Kishi Agent Patent attorney Etsu Tsukasa Kotani 1, -1-1 □,゛・. 1゛

Claims (1)

[Claims] 1. e[91 to 93% by weight and plastic by 9 to 7% by weight are mixed at room temperature, and this is mixed in the kneading section of the mixed line injection molding machine to plasticize the plastic. A method of manufacturing an electromagnetic core, etc., characterized by molding it into a predetermined shape by injecting it into a mold through an injection molding machine.