JPS62171515A - Bearing device - Google Patents

Abstract

PURPOSE:To lengthen the life of a bearing device and to achieve low vibration and low noise by coating the forward end portion of a shaft brought into contact with a bearing plate made of 66 nylon, or steel plate with ceramics to make the surface hardness larger than the hardness of a shaft by a specified value, and specifying surface roughness. CONSTITUTION:Ceramic coating 2 is applied only to the forward end portion of a shaft 5 brought into contact with a bearing plate 1 made by steel plate or polyester film, or made of 66 nylon, 6 nylon or polyacetal. The surface hardness of the ceramic coating 2 is larger than hardness of a shaft 5 by 0 to 400Hv, and surface roughness is 0.1-6.0mum. Thus, the life can be lengthened, low vibration and low noise can be achieved, impact resistance can be improved, the power consumption can be decreased to contribute to design of light, thin, short and small device.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a bearing device, particularly a thrust bearing device, used in a small motor serving as a tape drive source for, for example, a tape recorder or a videotape recorder.

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 using an example of a coreless DC motor with reference to FIGS. 3 and 4.

In FIGS. 3 and 4, reference numeral 5 denotes a shaft having an arcuate tip, which is rotatably supported by a sleeve bearing 9 provided on a frame 11. As shown in FIG.

A plurality of molded windings 6 and a commutator 7 integrally molded from a plastic molded material 8 are attached to the shaft 5 to constitute a rotor. 12 is a magnet fixed to the frame 11 facing the shaped winding 6; 13 is a yoke facing the magnet 12 via the shaped winding 6; 14 is a brush that comes into sliding contact with the commutator 7; 15 is the frame 1;
The bracket covers the opening at the end of the shaft 1, and a thrust receiver 10 for receiving the tip of the shaft 5 is installed at the center of the inner bottom.

In the above configuration, the shaft 5 is supported by a radial bearing 9, and when it rotates, the load in the thrust direction is transferred to the thrust receiving plate 1.
It is structured so that it can be received at 0. At this time, thrust receiving plate 1
For example, in the case of a system that uses magnetic force to apply a thrust load to prevent vertical movement of the rotor, the load received by 0 is 10 to 6 QOgr, and in the case of a shaft with a diameter of 1 to 2 mm, The diameter of the contact portion of the thrust plate at the tip is approximately 0.2 mm, and the load per unit area is 0.2 mm.
3 to 20 Kg f/cm”.

Problems to be Solved by the Invention The thrust receiver 10, which receives the load and rotates at high speed, is extremely susceptible to wear. For this reason, if the thrust bearing 10 is made of a hard material such as partially stabilized zirconia, silicon carbide, or ceramic such as alumina to compensate for its wear resistance, the steel shaft will wear out, but the ceramic bearing will crack due to impact. Such inconveniences may occur. The cracking of ceramics caused by impact can be solved by increasing the thickness of the ceramic itself, but this does not satisfy the needs for lighter, thinner, shorter, and smaller products.

The following table shows examples of the use of materials in conventional thrust bearings and examples of their various characteristics.

The test conditions in the table below are as follows: 1. Test temperature: room temperature 2. Rotation speed: 200-2200 rpm3. Rated output: 0. lW 4, voltage: 4.2V 5, current value: 100mA.

As a result of the above, an excellent bearing material is desired. The purpose of the present invention is to reduce the wear caused by sliding between the shaft and thrust receiving plate of a small motor, and at the same time, reduce wow and flutter. IN$i・Reduction of power consumption・
This aims to improve performance by reducing vibration and noise.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a ceramic coating on the contact surface of the bearing plate at the tip of the shaft.

Effect: By the above means, the life of the motor can be extended without causing mutual wear between the shaft and the bearing.

In addition, the slipperiness of the shaft is improved, and performance can be improved, and a light, thin, short, and small design becomes possible.

Example FIG. 1 shows an embodiment of the invention.

Note that the same parts as the above conventional configuration are given the same reference numerals.
The explanation will be omitted. In the figure, 1 is a shaft made of steel plate, polyester film, 66 nylon, 6 nylon, or polyacetal, and bearing plate 5 is a shaft.
Ceramic coating 2 is applied only to the tip of the shaft that comes into contact with the shaft. Grease 4 is applied to this sliding surface.
It is coated with.

FIG. 2 is a detailed view of the bearing section. It should be noted that the ceramic coating of the present invention does not have a surface hardness that is significantly different from that of a thrust bearing plate made of a steel plate like conventional ceramic bearings, but has a surface hardness that is not significantly different from that of a thrust bearing plate made of a steel plate.
The hardness varies from 650-750 to 850-950.
Select one. The surface roughness is set to 0.1 to 6.0 μm, and the sliding surface is coated with grease. In addition, the following materials and coating methods are used for the shaft 5.

1. The shaft as a base material is: a) Steel bar for crawling b) Aluminized steel bar c) SUS steel bar (SUS304.5US430 etc.) d)
Use other steel rods.

2. The coating method is a) Wet depping method b) One-way wet spray C) Dry powder coating method d) Dry electrostatic coating method e) Electrodeposition coating method etc.

The characteristics are explained in the table below. The test conditions in the table below are as follows: 1. Test temperature: normal temperature 2. Rotation speed: 200-2200 rpm3. Rated output: 0. IW 4, voltage: 4.2V 5, current value: 100mA.

6. Bearing 1 of the present invention: Micro Vickers hardness 650
~750 HV ones.

7. Bearing 2 of the present invention with a capacity of 50 to 850 Hv.

8. Bearing 3 of the present invention: 850 to 950 Hv.

It is.

As an example of the composition of the frit for ceramic coating, those shown in the table below can be used.

Margin below.

As is clear from the explanations in Table 3 and above, the present invention provides the following effects.

1) Improved wear resistance of the shaft tip and bearing plate enables smooth rotation and long life.

2) There is no formation of recesses due to wear of the shaft tip and bearing plate, and there is no vertical movement of the shaft due to minute movements of the shaft, resulting in an excellent bearing device with low levels of vibration and noise. I can do it.

3) Since the surface of the shaft remains smooth for a long time, power consumption can be reduced using this type of bearing device.

4) Since the shaft is coated with a ceramic coating, a bearing device with excellent impact resistance can be obtained.

5) Since a thin ceramic coating layer is sufficient, it is possible to obtain a bearing device that can be made lighter, thinner, shorter and smaller.

6) The ceramic coating surface is microscopically porous and can retain the applied grease for a long time.Even if the bearing plate is made of steel, it can be coated with polyester film, 66 nylon, 6 nylon, or polyacetal. It can also contribute to longer life.

As a result of 1) to 6) above, the quality of equipment using the bearing device of the present invention can be improved, the lifespan can be significantly extended, and equipment with a light, thin, short and small design can be realized.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a motor showing a first embodiment of the present invention;
FIG. 2 is a sectional view of a bearing plate according to another embodiment of the present invention;
FIG. 3 is a sectional view of a conventional motor, and FIG. 4 is a perspective view showing the configuration of a general rotor. Engineering: bearing plate, 2: ceramic coating, 5: old shaft. Name of agent Patent attorney Toshio Nakao 1 idiot Figure 1 1--Bearing plate 2--Ceramic coach-in 7゛5-Shaft Figure 2

Claims (5)

[Claims] (1) A bearing device characterized in that a ceramic coating is applied to the tip of the shaft that contacts the bearing plate. (2) The bearing device according to claim 1, wherein the bearing plate is made of any one of polyester film, nylon 66, nylon 6, and polyacetal. (3) Claim 1, characterized in that the bearing plate is composed of a motor case or a plate-shaped steel plate.
Bearing device as described in section. (4) The bearing device according to claim 1, wherein the surface hardness of the ceramic coating is 0 to 400 Hv harder than the hardness of the shaft. (5) The surface roughness of the ceramic coating should be 0.1~
Claim 1 characterized in that the diameter is 6.0 μm.
Bearing device as described in section.