JPH0561488B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a method for manufacturing a composite flywheel,
In detail, even though metal powder is compounded in multiple layers in synthetic resin (hereinafter simply referred to as resin), it is dispersed uniformly, and it has a large inertial force. The present invention relates to a method for manufacturing a composite flywheel, which allows the flywheel to be mass-produced by injection molding very economically.

Note that here, the recording/playback equipment refers to audio equipment such as general tape recorders, home stereos, and car stereos, as well as computer terminal equipment and the like.

2. Description of the Related Art Conventionally, flywheels have been used in recording and reproducing devices such as tape recorders to alleviate uneven feeding of magnetic tapes and the like.

This flywheel was generally manufactured by casting or forging metal with a large specific gravity.
This structure requires a balancing process such as cutting and polishing after a molding process such as casting, making the manufacturing process extremely complicated and expensive.

From this point of view, the present inventors first developed a flywheel with a sintered composition that can omit the above-mentioned balancing process and, unlike a cast structure, has fine voids uniformly distributed between metal powder particles. proposed (Tokuko Akira)
56-10698). This flywheel can appropriately adjust wow and flutter by adjusting the size, distribution, and occupation of voids, and can be manufactured by powder metallurgy, so there is no need for balance processing such as cutting and polishing. Although this flywheel has extremely low wow and flutter values, it is made entirely of expensive metal powder and manufactured using powder metallurgy, making the manufacturing process complicated. In addition, since high heat is required, cost is a major problem in flywheels for recording and playback equipment, where economic efficiency is important.

On the other hand, in recent years, with the development of electronic technology, audio equipment such as tape recorders has become smaller, and as a result, smaller flywheels are required, and with technological advances, even smaller motors are needed. As the output increases, the tolerance limits for wow and flutter required of flywheels are considerably relaxed compared to the past, and a smaller, lower cost flywheel is desired.

In other words, as recording and playback equipment becomes smaller as of today, the wow and flutter required for it varies depending on the specifications of the equipment, but is approximately 0.05 to 0.5.
%, and it is not necessarily necessary to have a strict value of 0.15% or less as in the conventional case, and there is no necessity to use a flywheel made by powder metallurgy.

In other words, while modern motors are becoming smaller,
As the output has increased, the requirements for wow and flutter on the flywheel have become less severe than in the past.On the contrary, tape recorders, such as the Walkman, have become smaller and lighter, and as a result, There are also increasing demands for flywheels to be smaller, lighter, and more economical.

Problems to be Solved by the Invention The purpose of the present invention is to solve the above-mentioned drawbacks.Specifically, it is possible to uniformly disperse a large amount of metal powder in a resin, mass-produce it by injection molding, and reduce wow and flutter to 0.05. We propose a method for manufacturing small-sized composite flywheels of ~0.5%.

<Structure of the invention> Means for solving the problems and their effects That is, the method of the present invention
When producing a composite flywheel containing 70 to 95% of the metal powder and having a specific gravity of 3.5 to 5.5 g/cm ³ , the metal powder is uniformly dispersed in the synthetic resin, and the metal powder has a diameter of 150 to 10 μm in the synthetic resin. It is characterized by adding metal powder, kneading it while heating and melting it, and then crushing it after cooling to form pellets, which are then formed into a flyfoil shape.

The above structure and its operation will be specifically explained below with reference to FIGS. 1 and 2.

First, FIG. 1 is a sectional view of an example of a flywheel manufactured by the method of the present invention, and FIG. 2 is an enlarged sectional view of a part thereof. In FIG. 1, reference numeral 1 indicates a flywheel, and this flywheel 1
As described below, the metal powder is 70 to 95 wt% (hereinafter referred to as
It is simply called %. ) is uniformly dispersed in synthetic resin,
It is integrally molded into a disk shape. That is, as shown in FIG. 2, the metal powder 2 is dispersed in the resin 3, increasing the specific gravity and the inertial force compared to the resin alone. Although the shape of the flywheel does not necessarily have to be as shown in FIG. 1, it usually has a shaft hole 1a in the center as shown in FIG.
is formed, and the rotating shaft 4 is mounted in this shaft hole 1a.
Furthermore, it is effective to increase the mass at a location as far away from the rotating shaft 4 as possible to increase the inertial force, and the rib portion 1b is usually configured to have a thick wall.

In addition, synthetic resins may be of any type depending on the molding method, but typical thermosetting resins include phenol resin, epoxy resin, polyester resin, melamine resin, furan resin, diallyl phthalate resin, thermosetting resin, and thermosetting resin. Examples include curable polybutadiene resin.

Typical thermoplastic resins include polyolefin resins, vinyl chloride resins, polyacetal resins, polyamide resins, polycarbonate resins, and various copolymers and modified products of these resins. From the viewpoint of viscosity, nylon is preferable.

Furthermore, metal powders include Fe, Zn, Sn, Pb,
Although Cu and its alloys are included, Fe
Flour is most preferred.

The particle size of the metal powder affects the physical properties of the flywheel, but when the particle size is increased, the metal powder
Since it is blended in a large amount, such as 95%, it tends to result in poor dispersion, and the surface smoothness and gloss are impaired.From this point of view, the thickness should be 150 μm or less and 10 μm or more.
That is, when the particle size is as small as 150 μm or less, the dispersibility is improved and the physical properties are also improved. However, depending on the type of metal, if it is too small, the activity will increase and gaseous substances will be generated when the composition is melted and heated, causing a decrease in physical properties.
The particle size shall be greater than or equal to the above.

Note that when resin and metal are mixed, additives such as coupling agents, dispersants, stabilizers, and fibrous reinforcing materials can usually be added.

In addition, the amount of metal powder to be mixed is determined so that the specific gravity is 3.5 to 5.5 g/cm ³ in relation to the resin content. There is a risk that the raw material will adhere to the inner wall surface of the outer casing of the cylinder, etc., or the stirring parts of the screw, blade, etc., and that the raw material will be severely abraded by the large amount of metal powder in the raw material. The more metal powder there is in the raw material, the more severe this adhesion and abrasion becomes, and from this point of view, the amount of metal powder mixed is preferably 95% or less. The lower limit of the amount of metal powder mixed is 70%, which varies depending on the specific gravity of the metal powder, but in order to obtain the wow and flutter required for tape recorders, etc., it must be mixed at 70% or more. It is from.

Next, the flywheel having the above structure can be molded in the following manner.

That is, 70 to 95% metal powder and 5 to 30% thermoplastic resin are kneaded while being heated and melted, and this is formed into pellets.Then, the pellets are then molded into a flywheel by injection molding, for example. do.
In order to increase the inertial force as a flywheel, it is necessary to increase the blending ratio of metal powder and improve its dispersibility. That is, it is extremely difficult to uniformly disperse and mix materials with large differences in specific gravity.
Moreover, it is extremely difficult to mix a large amount of metal powders with large differences in specific gravity. From this point of view, a flywheel is manufactured by first kneading metal powder and a thermoplastic resin to form pellets, melting these pellets, kneading them again, and then molding them under high pressure, for example, by injection molding.

Example Example 1 will be explained as follows.

Example 1 Iron powder and lead powder are mixed with nylon resin, silane coupling agent A-1100 (manufactured by Nitto Unicar Co., Ltd.) is added to these, and these are heated and melted at a temperature of 250°C. The mixture was kneaded while applying pressure, and after cooling, it was crushed and formed into various pellets with a diameter of about 3 mmφ. After drying these pellets, a flywheel having the shape shown in FIG. 1 was molded using a screw-type injection molding machine at a cylinder heating temperature of 255°C, a mold temperature of 80°C, and an injection pressure of 850 kg/cm ² .

The relationship between the amount of metal powder blended and the specific gravity of these flywheels was determined as shown in Figure 3.Among these flywheels, the wow/flatter was about 0.2 to 0.3 for those with a specific gravity of 3.8 to 4.5 g/ ^cm3 . The iron powder was uniformly dispersed throughout.

In Fig. 3, symbol A indicates a product containing iron powder, and symbol B indicates a product containing lead powder.

<Effects of the Invention> As explained in detail above, the present invention is a method for producing a flywheel in which a large amount of metal powder is uniformly dispersed in a synthetic resin and has a specific gravity of 0.5 to 4.5 g/cm ³ . Even though the metal powder is blended, it is pelletized before injection molding, so
Metal powder is uniformly and highly filled, and injection molding allows
Can be manufactured economically.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an example of a flywheel manufactured according to the present invention, FIG. 2 is an enlarged view of a part of FIG. 1, and FIG. 3 is a graph showing the relationship between the amount of metal powder mixed and specific gravity. . Code 1...Fly foil, 2...Metal powder, 3
……resin.

Claims (1)

[Scope of Claims] 1. To produce a composite flywheel containing 70 to 95% metal powder by weight, the metal powder being uniformly dispersed in a synthetic resin, and having a specific gravity of 3.5 to 5.5 g/cm ³ In some cases, the diameter is 150 to 10 μm in synthetic resin.
After adding metal powder and kneading it while heating and melting it, after cooling it, it is crushed to form pellets, and then,
A method for manufacturing a composite flyfoil, characterized by molding it into a flyfoil shape. <Purpose of the invention>