JPS6035599B2 - electric motor bearing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bearing device for a motor used in a vacuum cleaner or the like, and aims to extend the life of oil-less metal during high-speed rotation.

Conventionally, oil-less metals have been widely used in place of ball bearings and roller bearings due to their low cost, but electric motors used in vacuum cleaners and the like rotate at extremely high speeds (1500pm to 3000pm). Because oil-less metal is used in
, rarely used and abandoned.

The present invention aims to maintain a long service life even when used at high speed rotation while using the above-mentioned oil-less metal which is inexpensive in cost.

As shown in FIG. 1, a conventional oil-less metal has a motor shaft 2 inside an oil-less metal 1, and the oil-less metal is impregnated with lubricating oil. The oilless metal 1 is held by a motor bracket 3 and a metal presser spring 4, and around the oilless metal 1 there is a felt 5 impregnated with lubricating oil. In the above configuration, when the motor shaft 2 rotates, the lubricating oil impregnated in the oilless metal oozes out for lubrication.

This structure is widely used in sewing machine motors, etc., and has a lifespan of about 100 hours due to the low rotation speed (10,000 rpm or less). Frictional heat is generated and the viscosity of the lubricating oil decreases due to this heat. Normally, the operating temperature of lubricating oil is 5,000 to 6,000 ℃ for highly viscous lubricating oil, but if this temperature is exceeded, lubrication will not work properly. It will no longer be done. This increases frictional resistance and generates even more frictional heat. As a result, the lubrication becomes even worse, and this vicious cycle is repeated, causing the temperature of the oil-less metal 1 to rise. In addition, due to this heat, the lubricating oil evaporates and decreases, and since the rotation speed of the motor shaft 2 is high, a large amount of lubricating oil flows through the motor shaft 2 and comes out to the outside, so the service life ends in a very short time. It reaches the point where it becomes metal burnt or metal rattle. According to experiments, the rotation speed is 1950 p.
m, vertical diameter 6.35 mm, minimum 2 female temples, maximum 15. The only space available was Sodera-ma.

Therefore, in order to solve the above problem, as shown in FIG. {c) The bracket 3' is made blind to reduce the volatilization of the lubricating oil, and {c) an oil drain is installed to eliminate the lubricating oil flowing through the motor shaft 2 to the outside. 6, {d) Even if the lubricating oil is used up, new lubricating oil is continuously supplied to the oil-less metal 1.
An oil cap 7 for holding lubricating oil to be supplied to the engine was considered.

With the above configuration, when the motor shaft 2 rotates at high speed, the precision of the oil-less metal 1' and the motor shaft 2' is high, so the frictional resistance is small and the generation of frictional heat is small. Less is.

In addition, even if the lubricating oil evaporates, it will not evaporate from the bracket 3' side because the bracket 3' is blind, and the lubricating oil traveling along the motor shaft 2 will be blown away by the oil drainer 6 due to the centrifugal force caused by the rotation of the motor shaft 2, and the felt It is adsorbed to 5′,
Used again for lubrication. Furthermore, since a large amount of lubricating oil is retained by the oil cap 7, the life of the oil-less metal 1' is extended. According to experiments, the lifespan of one with a 20 to 157 hour lifespan was extended to a minimum of 390 hours and a maximum of 1,630 hours.

However, the lifespan varies widely, with the lowest value being 39
Due to the uneven time, it could not be used as a motor bearing for vacuum cleaners, etc.

The present invention dramatically improves the life of the bearing by further improving the above configuration, and embodiments thereof will be described below with reference to the drawings.

In Fig. 3, the oil-less metal 8 is impregnated with lubricating oil, the motor shaft 9 is inserted into the oil-less metal 8, and the oil-less metal 8 has a bracket on one side and a metal holder on the other side. It is held by a spring 11.

There is a felt 12 around the oil-less metal 8, and the felt 12 is impregnated with grease. There is an oil holder 13 on the outside, and an oil spout 14 attached to the motor shaft 9 is provided inside the oil holder 13. With the above configuration, when the motor shaft 9 rotates, the lubricating oil impregnated in the oil-less metal 8 seeps out, and lubrication is performed.

As the electric motor shaft 9 rotates at high speed, heat is generated due to friction with the oilless metal 8, the temperature of the bearing increases, and the viscosity of the lubricating oil decreases. Eventually, when the lubricating oil no longer provides normal lubrication, the felt The grease soaked in the bearing part 12 melts due to the heat and becomes liquid to lubricate the bearing part. The lubricating oil and grease flowing along the motor shaft 9 are blown off along the oil spout 14 by the centrifugal force caused by the rotation of the motor shaft 9, and are received by the oil receiver 13, and then the felt 12
Return to It is then used again for lubrication. According to experiments, with a rotation speed of 2200 pm and a bearing of 6.35 mm, a minimum of 172 song hours and a maximum of 240 feeding hours were achieved, compared to a conventional rotation speed of 19.
At 50pm, we were able to extend the lifespan of a product with a minimum of 399 hours and a maximum of 163 hours.

In addition, in the experiment, only grease was applied to the felt, but felts that are frequently used at low temperatures are
It would be better to reduce the amount of grease and increase the amount of lubricating oil. It is necessary to pay sufficient attention to the compatibility between grease and lubricating oil, and it is important to determine this through experiments. The normal operating temperature of lubricating oil has an upper limit of 50oo to 60oo;
If it exceeds 00, it will hardly exhibit any lubricity. Grease is used at an overlap in operating temperature with lubricating oil, so select one that becomes liquid at around 550°C, and use lubricating oil for bearing oil salt up to 50°C.
It is best to use a combination of lubricating oil and grease for lubrication up to 80 oo, and use grease for 80 oo or more. As described above, according to the present invention, in addition to the oil-less metal, a supporting lubrication structure is provided, and by using grease together with oil to lubricate the above-mentioned bearing, it has a long life even when used at high speeds and high temperatures. It can provide bearings, and its industrial value is extremely large.

Brief Description of the Drawings Figure 1 is a sectional view of a conventional bearing using oil-less metal, Figure 2 is a sectional view of a bearing using oil-less metal as a countermeasure for the conventional example, and Figure 3 is a bearing of the present invention. FIG. 2 is a cross-sectional view of a bearing device in one embodiment.

8...Oil-less metal, 9...Electric motor shaft, 12...
felt.

Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1 The electric motor shaft is rotatably supported, and has an oil-less metal impregnated with lubricating oil and a felt positioned so as to surround this oil-less metal, and this felt is coated with grease or grease and lubricating oil. A bearing device for an electric motor that is impregnated with lubricating oil and has an overlap between the upper limit temperature for use of lubricating oil and the temperature at which grease becomes liquid.