JPH01269718A - Bearing device for motor - Google Patents

Abstract

PURPOSE:To avoid abrasion due to contact between a shaft and a bearing by providing a thrust plate comprising a magnet and a spiral groove bearing which has spiral grooves on the opposite surface to the thrust plate and is formed from superconducting ceramics. CONSTITUTION:A thrust plate 12a comprising a magnet is fitted to the forward end of a shaft 1, and a spiral groove bearing 13a formed by superconducting ceramics is disposed on a bracket 10 opposite to the thrust plate. A spiral groove is provided on the surface of the spiral groove bearing 13a that is opposite to the thrust plate 12a, and grease is disposed therebetween. The resiliency due to Meissner effect acts across the bearing 13a and the thrust plate 12a, so that even when the rotation of the shaft 1 is stopped, the thrust plate 12a is kept from contacting the bearing 13a. During rotation, the shaft 1 can be supported out of contact by the spiral groove.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a motor bearing device used as a thrust bearing for a small motor that serves as a tape drive source for, for example, a tape recorder, a video tape recorder, or the like.

BACKGROUND OF THE INVENTION In recent years, with the expansion of the domestic and industrial markets, there has been an increasing need for compact motors to be lighter, thinner, and smaller, and there has been a desire for the development of ultra-compact motors. This motor will be explained with reference to FIG. 3 using an example of a coreless DC motor.

In FIG. 3, reference numeral 1 denotes a shaft having an arcuate tip, which is rotatably supported by a radial bearing 3 provided on a frame 2. As shown in FIG.

A plurality of molded windings 5 and a commutator 6 integrally molded from a plastic molded material 4 are attached to the shaft 1 to constitute a rotor. 7 is a shaped winding 5 (a magnet fixed to the frame 2 facing the magnet; 8 is a yoke that faces the magnet 7 via the shaped winding 5; 9 is a brush that slides into contact with the commutator 6; 10 is a magnet fixed to the frame 2); This is a bracket that covers the opening at the end of frame 2.
A thrust bearing 11 is equipped to receive the tip of the shaft.

In the above configuration, the shaft 1 is supported by the radial bearing 3, and when it rotates, the load in the thrust direction is transferred to the thrust bearing 1.
It is structured to receive 1. At this time, thrust bearing 1
For example, in the case of a system that uses magnetic force generated in the rotor to apply a thrust load to prevent the rotor from moving up and down, the load that it receives is 10 to 600 g. In the case of a shaft, the diameter at the thrust bearing contact portion at the tip is approximately 0.2+nm, and the load per unit area is 0.3 to 20 kg/fc+J. The thrust bearing 11 is subject to the above-mentioned load and rotates at high speed, so it is extremely susceptible to wear. Therefore, in order to supplement the wear resistance of the thrust bearing 11, it is made of a hard material, for example, partially stabilized zirconia, silicon carbide, or ceramic such as alumina.

Problems to be Solved by the Invention However, with the above-described configuration, problems occur such that the steel shaft 1 wears out or the ceramic thrust bearing 11 cracks due to impact.

This cracking caused by impact on ceramics can be solved by increasing the thickness of the ceramic itself, but this has the disadvantage that it cannot satisfy the needs for light, thin, short and small products.

On the other hand, when a thrust bearing is provided with a spiral groove to form a hydrodynamic bearing in order to reduce wear on the bearing part, the amount of fluid collected through the groove at startup is small and there is no pressure. , the bearing and shaft are in contact,
At that time, wear and tear is unavoidable.

Under the above circumstances, an excellent bearing device is desired.

The present invention aims to avoid wear due to contact between the shaft of a small motor and a thrust bearing, and at the same time improve performance by reducing wow and flutter, power consumption, and vibration noise.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention includes a thrust plate made of a magnet provided at one end of a rotor having a shaft, and a spiral groove facing the thrust plate. The spiral groove bearing is made of superconducting ceramics.

Alternatively, the rotor includes a thrust plate made of superconducting ceramics provided at one end of a rotor having a shaft, and a spiral groove bearing that faces the thrust plate and has a spiral groove on the opposing surface, and the spiral groove bearing is made of a magnetic material. The spiral groove bearing is formed with a magnetic coil and an electromagnetic coil is wound around the spiral groove bearing.

According to the above configuration, even when the rotor is stationary, the thrust plate and the spiral groove bearing maintain a non-contact state due to the Meissner effect. When the rotating body rotates, the spiral groove allows the thrust plate and the spiral groove bearing to maintain a non-contact state. Therefore, the life of the motor can be extended without deterioration of equipment integrity due to wear of bearings and shafts, and a motor of always stable quality can be obtained.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 and 2. Note that the same parts as the conventional configuration are given the same reference numerals as in the conventional example, and the explanation thereof will be omitted.

FIG. 1 shows an embodiment of the first invention.

In the figure, a thrust plate 12a made of a magnet is attached to the tip of a shaft 1, and a spiral groove bearing 13a made of ceramic is provided on a bracket 10 facing the thrust plate 12a. A spiral groove is provided on the opposite surface of the thrust plate 12a of this spiral groove bearing 13a, and grease (not shown) is provided between the thrust plate 12a (!l: spiral groove bearing 13a). This bearing 13a and thrust plate 12a
A repulsive force due to the Meissner effect acts between the thrust plate 12a and the bearing 13a (therefore, even when the shaft 1 stops rotating, the thrust plate 12a and the bearing 13a do not come into contact with each other. Also, during rotation, the spiral groove keeps the shaft 1 in a non-contact state). can be pivoted.

FIG. 2 shows an embodiment of the second invention, in which an electromagnetic coil 14 made of superconducting ceramic material is wound around a spiral groove hair ring 13b made of a magnetic material to form a superconducting magnet, and a thrust plate 12b is made of superconducting ceramic. are doing.

With this structure, when the motor is stationary, the electromagnetic coil 14 is energized to generate magnetic flux, and the thrust plate 12b is refracted due to the Meissner effect, causing the shaft to float and bring the thrust plate 12b and the bearing 13b into a non-contact state. I can do it.

Examples of superconducting ceramics used at this time are described below.

Examples of materials that exhibit superconductivity at an absolute temperature of 90°C include Y
Ba2Cu307- can be used.

During production, first, the raw material powder is crushed and mixed.

It is baked at 900° C. in air for 5 hours and then pulverized, and this process is repeated to improve uniformity.

The powder is shaped, sintered by heating in air or oxygen at 930°C to 950°C for 5 hours, and cooled in a furnace.

5rYBa2 is a material that exhibits superconductivity near normal humidity.
Cu3 07- is known. (Ihara et al., JAP
ANESE JouRNAL OF APPIED
PHYSIC8), Vol. 26. No.

8, August 1987. When producing PP, 161-, raw material powder is first ground and mixed. 9 it
After firing in air at 20°C for 5 hours, the mixture is pulverized and repeated three times.

The powder is shaped, sintered by heating at 1000° C. in air for 5 hours, and cooled in a furnace. The sintered body thus produced exhibits superconductivity at 338 K (65° C.).

Effects of the Invention As is clear from the above description, the present invention provides the following effects.

There is no contact between the shaft and bearing when the motor starts and stops, so there is no wear on the shaft and bearing. Furthermore, rotational lock of the motor does not occur due to foreign matter entering the herringbone.

As a result, the quality of the small motor has been improved and its lifespan has been significantly extended, making it possible to realize a motor with a light, thin, short and small design.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the first aspect of the present invention, in which (a) is a sectional view of a motor, (b) is a perspective view of a spiral groove bearing, and FIG.
1 shows an embodiment of the invention, in which (a) is a sectional view of a motor, (b) is a perspective view of a spiral groove bearing,
FIG. 3 is a sectional view of a conventional motor. 1...Shaft, 12a, 12b...
Thrust plate, 13a, 13b... Spiral groove bearing, 14... Electromagnetic coil. Name of agent: Patent attorney Toshio Nakao (1 person) Figure 1 1-1-Shafhi 2a (b) Figure 2 + 2b --- Thrust Express Figure 3

Claims (2)

[Claims] (1) A thrust plate made of a magnet provided at one end of a rotor having a shaft, and a spiral groove bearing that faces the thrust plate and has a spiral groove on the opposing surface, and the spiral groove bearing is made of superconducting ceramics. Motor bearing device made of. (2) A thrust plate made of superconducting ceramics provided at one end of a rotor having a shaft, and a spiral groove bearing that faces the thrust plate and has a spiral groove on the opposing surface, and the spiral groove bearing is magnetically attached. A motor bearing device in which an electromagnetic coil is wound around the spiral groove bearing.