JPS60249681A - Enclosed compressor - Google Patents

Abstract

PURPOSE:To make stable lubrication performable all the time even if oil viscosity varies, by installing plural pieces of oil grooves, being different in a sectional form each, in a shaft or a main bearing. CONSTITUTION:Plural pieces of oil grooves 34a and 34b are installed on a lubricating surface of a shaft or a main bearing 35 in a parallel manner. Each of these oil grooves 34a and 34b is being formed so as to be different in width and depth each. That is to say, the width and depth of the oil groove 34a should be set to an optimum value to oil in low viscosity. And, the width and depth of the oil groove 34b should be set a larger value than that of the optimum groove 34a to oil in high viscosity. Therefore, when oil viscosity is high, lubricating oil is mainly fed to the groove 34b but when the oil viscosity is low, the groove 34a becomes easy to be lubricated. Thus, even if there is a variation in the oil viscosity, each groove acts on each other so that stable lubrication is made performable all the time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a hermetic compressor used in a refrigeration cycle or the like, and particularly to a hermetic compressor characterized by an oil supply mechanism for a main bearing.

[Technical background of the invention and its problems]

FIG. 1 is a longitudinal sectional view showing an example of a hermetic compressor. The hermetic compressor 10 includes an electric motor 12 disposed in the upper part of the hermetic casing 11, and a motor 12 extending downward from the electric motor 12.
A shaft 14 integrally formed with a large diameter portion 13 eccentric to the lower end side, disposed above and below so as to sandwich the large diameter portion 13,
A main bearing 15 and a sub-bearing 1 that support the shaft 14
6. A cylinder 17 located between the main bearing 15 and the auxiliary bearing 16 and forming a compression device; a large diameter portion 1 inside the cylinder 17;
3 and the rollers 18 and 18 disposed in an externally fitted state.
It is provided with a blade 19 that makes elastic contact with the blade 19.

Further, an oil tank 21 in which lubricating oil is stored is provided at the lower part of the casing 11, and the lubricating oil is supplied from inside this oil tank 21 to the sliding portion between the shaft 14 and the main bearing 15. The bearings are lubricated. This lubricating oil is supplied by an oil pump 23 provided in the center hole 22 of the shaft 14 and a spiral oil groove 24 provided on the outer circumference of the shirts 1 to 14 or on the inner circumferential surface of the main bearing 15. This is done by pumping up the water.

In a conventional hermetic compressor, the spiral oil groove 24 is
Since only one shaft is provided, there is a problem in that the amount of oil supplied to the main bearing section fluctuates due to changes in the viscosity of the oil. tJ - that is, the center hole 22 of shaft 1/I
The oil pump 23 provided inside has a characteristic that the amount of oil supplied increases as the viscosity of the oil decreases, and the spiral oil groove 24
On the contrary, as the viscosity of the oil decreases, the amount of oil supplied decreases, so the amount of oil supplied to the main bearing as a whole is
As shown in the figure, there is a tendency for the viscosity of the oil to decrease rapidly as it decreases.

For this reason, when the viscosity of the oil decreases, such as when the hermetic compressor overheats, the amount of oil supplied decreases rapidly, sometimes causing seizure in the main bearing.

[Purpose of the invention]

The present invention has been made in consideration of these points,
The purpose of the present invention is to provide a highly reliable hermetic compressor in which the amount of oil supplied to the main bearing does not vary greatly even if the viscosity of the oil changes, and stable lubrication is always performed.

[Summary of the invention]

The present invention is a hermetic compressor in which a shaft or a main bearing is provided with a spiral oil groove for oil supply, in which a plurality of oil grooves are provided in parallel, and each oil groove has a cross-sectional shape. They are characterized by being different from each other.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a longitudinal sectional view showing the main bearing 35 used in the hermetic compressor according to the present invention. In the present invention,
The main bearing 35 has two spiral oil grooves parallel to each other.
Compared to 4b, the depth and groove width are different. That is, as shown in FIG. 4, one oil groove 34a has a groove depth of 61 mm and a groove width of 81 mm, and the other oil groove 34b has a groove depth of 61 mm and a groove width of 81 mm.
The groove has a depth of 62 mm and a width of 82 mm.

Generally, the amount of oil flowing through a spiral oil groove is expressed by the following equation.

Here, Q: Flow rate U; Peripheral speed B: Groove width δ: Groove depth μ: Oil viscosity (i-?-: Compression gradient in the longitudinal direction of the groove By differentiating the value with δ, δ−3UIi ・・・・・・・・・・・・・・・・・・
...... (2) dP/dx.

In equation (2), the viscosity μ changes depending on temperature, refrigerant penetration, etc., and the optimum value of the groove depth δ changes accordingly. In other words, the lower the viscosity μ, the smaller the optimal value of the groove depth δ, and conversely, the higher the viscosity μ, the smaller the groove depth δ.
The optimal value of becomes large.

Therefore, the groove depth δ1 of one oil groove 34a is set to an optimal value for low viscosity oil, and the groove depth δ2 of the other oil groove 34b is set to an optimal value for low viscosity oil.
By setting JitQ to the optimum value for high viscosity oil, the maximum flow JitQ can always be achieved using either oil groove, regardless of whether the oil viscosity is low or high. can be secured.

In this embodiment, when the viscosity of the oil is relatively high, such as at the start of operation, the main bearing is mainly supplied through the deep oil groove 34b, and when the temperature becomes high during operation, The main bearing is mainly supplied with oil through the oil groove 34a, which has a small groove depth, and the overall amount of oil supplied is kept stable, almost unaffected by changes in viscosity, as shown in Figure 5. It will be done.

Therefore, even if the viscosity of the oil decreases at high temperatures, the main bearing will not run out of oil, and even if the viscosity of the oil increases at low temperatures, the amount of oil supplied will be too large and the oil level in the oil tank 21 will not occur. does not decrease.

In this embodiment, an example is shown in which the oil groove is provided on the inner circumferential surface of the main bearing 35, but it may be provided on the outer circumference of the shaft 14 that slides on the inner circumferential surface of the main bearing 35. Moreover, three or more oil grooves may be provided in order to more appropriately respond to changes in oil viscosity.

〔Effect of the invention〕

As explained above, according to the present invention, a plurality of oil grooves are provided in parallel with a cross-sectional shape suitable for each oil viscosity, so even if the oil viscosity changes, A stable supply of oil can be ensured at all times, and accidents such as seizure of the main bearing can be prevented. Furthermore, the absolute amount of oil supplied to the main bearing section is increased, and the reliability of lubrication of the main bearing section can be improved.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view showing an example of a conventional hermetic compressor, and Figure 2 shows the relationship between the amount of oil supplied and the viscosity of the oil groove installed in the main bearing of the conventional hermetic compressor. FIG. 3 is a vertical sectional view showing the main bearing of the hermetic compressor according to the present invention, and FIG.
This figure is a partially enlarged cross-sectional view of the main bearing shown in FIG. 3, and FIG. 5 is a diagram showing the relationship between the amount of oil supplied and the viscosity when the oil supply mechanism according to the present invention is used. 14...Shaft, 34a, 34b...Oil groove, 3
5... Main bearing.゛Applicant's Representative Ino Mata No. 1 Fig. 2 tb Koji Fig. 4 Fig. 5 Section

Claims (1)

[Claims] In a hermetic compressor in which a spiral oil groove for oil supply is provided on the shaft or main bearing, a plurality of oil grooves are provided in parallel, and each oil groove has a different cross-sectional shape. A hermetic compressor characterized by: