JPH0193617A - Radial bearing - Google Patents

Abstract

PURPOSE:To prevent the marring of a rotary shaft and suppress the promotion of wearing of a bearing in general by forming a curvature on end surfaces of a radial bearing for supporting the rotary shaft. CONSTITUTION:A material tablet 1 formed of glass carbon, phenol resin and a small amount of additives of surface active agent and grease is inserted into a lower mold 5, and is hardened with heat under pressure by an upper mold 4 to thereby form a resin bearing 3. A sliding surface 3a of the radial resin bearing 3 is formed at its opposite ends with curved surfaces 6. In this manner, as the curved surfaces 6 are formed at opposite ends of the sliding surface 3a for supporting a rotary shaft, marring of the rotary shaft can be very much suppressed. The end surfaces of the bearing may be made elliptical rather than circular. Further, the resin bearing may be replaced by a ceramic bearing or an oil containing sintered metal bearing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radial bearing that supports a rotating shaft in a radial direction.

[Conventional technology]

Conventionally, in this type of radial bearing, the end face of the bearing that supports the rotating shaft is chamfered, but as a result of forming the chamfer, an edge is created between the chamfer and the bearing surface, and this edge It was found that the rotating shaft could be scratched depending on the part.

If the rotating shaft is scratched, the edge portion of the bearing will wear out, and the resulting wear powder will further accelerate the wear of the entire bearing. Furthermore, there is also a drawback that the sliding resistance between the rotating shaft and the bearing increases due to scratches on the rotating shaft.

[Purpose of the invention]

An object of the present invention is to prevent the rotating shaft from being scratched and to prevent accelerated wear of the entire bearing.

[Means to solve the problem]

The present invention provides a radial bearing that supports a rotating shaft in a radial direction, in which the end surface of the radial bearing that supports the rotating shaft is curved.

〔Example〕

Examples of the present invention will be described below.

Since the radial bearing in the embodiment of the present invention is a resin bearing containing fine particles of amorphous carbon and plastic, this resin bearing will be described first.

First, glassy carbon, which is a form of carbon in an amorphous state, is produced. This glassy carbon is made of spherical particles, and the glassy carbon made of spherical particles is produced based on a resin material made of spherical particles.

The above-mentioned resin material consisting of spherical particles is produced by melting thermosetting resins such as epoxy resins and polyimide resins, and thermoplastic resins such as polyamide resins, polyphenylene sulfide resins, and polyetherketone resins, and then converting the molten resin into gas or It is generated by ejecting it into a fluid such as a liquid. Other methods for producing resin materials made of spherical particles include coating a core made of inorganic particles with the resin obtained as described above, and granulating fine resin powder with a solvent or the like. The core material of the resin material made of spherical particles is thermally stable. The shape of the spherical resin is not limited to a true sphere, but preferably a true sphere, an ellipsoid, or a teardrop shape.

Then, the resin material made of spherical particles produced as described above is heat-treated at 500 to 2500°C in an inert gas such as nitrogen or 113% Ar to form a glassy carbon material made of spherical particles. I got it. In this example, the particle size of the glassy carbon was all 5 μm or less.

The glassy carbon and phenol resin obtained as described above were mixed with a glassy carbon content of 70χ and a small amount of surfactant and grease were added to form a material tablet 1.
This tablet 1 was put into a mold 2 and molded as shown in FIG. 1 to form a bearing body 3.

The mold 2 is composed of an upper mold 4 and a lower mold 5, and the lower mold 5 for heating and pressurizing is formed into a protruding rod shape and is used to form a rotating shaft sliding surface of a resin bearing. It has a rotating shaft portion 5a and an annular groove portion 5b formed so as to surround the suspect rotating shaft portion 5a. The above-mentioned suspicious rotating shaft part 5a
A curved surface portion R is formed at the boundary between the groove portion 5b and the annular groove portion 5b. At the time of resin bearing molding, the material tablet 1 is supplied and installed in the recessed groove portion 5b. - A pressing part 4a is formed in the onion mold 4 for pressing the material tablet 1 supplied into the groove part 5b of the lower mold 5 during molding. The pressing portion 4a is configured to enter into the recessed groove portion 5b from the opening of the recessed groove portion 5b and press the molding material so as to seal the recessed groove portion 5b during molding.

A protrusion 4C having a curved surface R on the outer circumferential side is provided at the inner tip of the pressing portion 4a.

Therefore, when the material tablet 1 is put into the lower mold 5 and hardened under pressure and heat by the upper mold 4 to form the resin bearing 3,
As shown in FIG. 2, when the radial resin bearing 3 is molded, a curved surface 6 is formed at the end of the sliding surface 3a of the molded resin bearing 3.

As a result of forming the bearing end surface of the sliding surface 3a that supports the rotating shaft into the curved surface 6 in this way, it is possible to suppress the jaggedness of the rotating shaft to a very small level.

FIG. 3 shows another embodiment of the radial resin bearing according to the present invention, in which the bearing sliding surface 7 has a circular cross section. Note that the bearing sliding surface may not be circular but may be elliptical.

As a modification of the above embodiment, glassy carbon of 5μ
Even when a bearing body was formed by a method similar to the above using a mixture of the following fine grains and large diameter grains of 20μ, substantially the same effects as in the above example were obtained. This result shows that if glassy carbon contains fine particles, it improves fluidity during molding, ensuring high dimensional stability during molding, and also increases bonding strength with plastic. The glassy carbon does not fall off, resulting in extremely excellent wear resistance, low friction properties, and heat resistance.It has been found that the most preferable content of glassy carbon is 85 to 90χ.

In the above example, the particle size of the large-diameter particles is 20μ, but it is not limited to 20μ (If the glassy carbon contains fine particles, the particle size of the large-diameter particles is not a big problem No. The shape of the glassy carbon is not limited to spherical, but may be crushed.

In the above embodiment, a resin bearing was explained, but
The end portion of the bearing sliding surface of a ceramic bearing or a sintered metal oil-impregnated bearing may be a curved surface.

Next, an example in which the resin bearing described above is applied to a stepping motor will be described with reference to FIG. 4.

In Figure 4, 8 is a rotating shaft rotated by a motor, and the rotating shaft 8 is rotatably held by two bearings 9 and 10. In Figure 0, a load is applied to the rotating shaft on the right side. For this reason, the load on bearing 9 is small;
The load applied to the bearing IO becomes large. Therefore, in this embodiment, a sintered metal oil-impregnated bearing was used as the bearing 9, and the aforementioned resin bearing, which has better wear resistance than a sintered metal oil-impregnated bearing, was used as the bearing 10. In this way, it is possible to reduce costs while minimizing bearing wear.

Incidentally, if the combination of the sintered metal oil-impregnated bearing and the resin bearing described above does not have sufficient wear resistance, the resin bearing of the present invention may be used as the bearing 9, and a ball bearing may be used as the bearing 10. .

〔Effect of the invention〕

As explained above, according to the present invention, in a radial bearing that supports a rotating shaft in the radial direction, the bearing end surface that supports the rotating shaft of the radial bearing is curved, so that scratches on the rotating shaft can be prevented. This can prevent the bearing from accelerating wear as a whole.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the manufacturing process of the bearing in the present invention, Figure 2 is a diagram showing the manufacturing process of the bearing in the present invention.
3 is a sectional view of a bearing according to another embodiment of the present invention, and FIG. 4 is a side sectional view showing an example of application to a motor. 3... Resin bearing 3a... Sliding surface 6... Curved surface 7... Bearing sliding surface

Claims (1)

[Claims] A radial bearing that supports a rotating shaft in a radial direction, characterized in that a bearing end surface of the radial bearing that supports the rotating shaft is a curved surface.