US3482769A

US3482769A - Sealed motor-compressor,especially for small refrigerating units

Info

Publication number: US3482769A
Application number: US702921A
Authority: US
Inventors: Bendt Wegge Larsen
Original assignee: Danfoss AS
Current assignee: Danfoss AS
Priority date: 1968-02-05
Filing date: 1968-02-05
Publication date: 1969-12-09
Anticipated expiration: 1986-12-09

Description

B. w. LARSEN 3,482,759 SEALED MOTOR-COMPRESSOR, ESPECIALLY FOR SMALL REFRIGERATING UNITS Filed Feb. 5. 1968' Dec. 9, 1969 2 e 17 [A 7 18 U United States Patent US. Cl. 230-206 6 Claims ABSTRACT OF THE DISCLOSURE The invention relates to sealed motor-compressor units of the type having an open lubricating oil sump in the lower part of the housing from which oil is conveyed to various parts of the unit for lubricating and cooling purposes. In this type of unit the oil drains freely from the various parts of the unit back to the sump without the use of guided return paths such as channels and pipes.

In prior art units of this type the return of oil to the sump involves the direct dripping of the oil into the sump accompanied by relatively loud and undesirable drip noises.

In the present invention the oil is also allowed to return freely to the sump without the use of channels or pipes but at one or more drain points where dripping would otherwise occur there is or are provided guide elements in the form of wires, threads, strings or bands, etc., which hang vertically and function to allow oil to run silently down these elements to the sump instead of dripping directly from the drain points to the sump.

This invention relates to a sealed motor-compressor, especially for small refrigerating units, with circulated lubricating oil part of which latter drains ofi the stator or the compressor.

In motor-compressors of this type, part of the oil collects on stationary components and drips off into the oil sump. The quantity of the dripping oil may be considerable, because the compressors operate with a surplus of oil suflicient for the latter to be used not only as a lubricant but also as a coolant.

Many special measures have been adopted, in modern motor compressors, in order to lower the noise level. The present invention has for its object, still further to reduce the generation of noise.

According to the invention, this object is achieved in that, at points of the stator or the compressor at which oil drains off a guide element is attached which guides the oil at least over part of its return path towards the sump.

In this way the dripping noise is eliminated which, given a substantial dropping height such as encountered, for example, in a motorcompressor with vertical shaft and high-up compressor, can become a considerable nuisance, especialy if the dripping noise occurs at irregular intervals.

The guide element may extend from the dripping point to the oil sump or to a point closely adjacent thereto. The oil will then return to the sump with dripping or, at least, drip only from a negligible height. Alternatively, the guide element extends from the draining point to the wall of the housing. From there it can likewise return to the sump without making a dripping noise.

In many cases it is useful to provide welldefined draining points. In the case of a motor-compressor with vertical shaft and high-up compressor, for example, this may be done in that the draining point is an aperture in the wall of the motor-carrying element on the side facing the stator. Obviously, it is also possible to provide every one of a number of such draining points with a guide element.

Guide elements can be provided in the shape of very simple, inexpensive components. For example, the guide element may be a metal wire or band. Also plastic threads or bands may be used. The material may be stifi, resilient or even soft.

An embodiment of the invention has been illustrated diagrammatically in the accompanying drawing which shows a sealed motor-compressor for a small refrigerat ing unit in part-sectional side-elevation.

In a housing consisting of two

halves

1 and 2 is arranged a motor-compressor 3. It consists of a motor section 4 and a compressor section 5, the two sections being connected by means of a motor-carrying element 6. The motor-compressor is suspended by means of several supports 7 which are fixed on the motor-carrying element 6 and supported, via spiral-wound coil springs 8, on a strap 9 inserted in the housing. For claritys sake this support arrangement has only been illustrated partially; moreover, further components such as connection pipes for the coolant, connection nipples, etc., have likewise been omitted.

The only components of the motor section 4 which have been shown here are the stator 10 with its winding 11, and the lower end 12 of the hollow motor crankshaft which is driven by the rotor. The shaft end 12 projects into the sump 13 and, in known manner, conveys oil to the lubricating points, due to its hollow-cone formation. Surplus oil is thrown off in the region of the upper shaft end 14, to be intercepted by the housing, and returns to the sump along the wall of the latter. Further amounts of oil are discharged in the main bearing of the shaft, in the region of the motor-carrying element 6, in the crank bearing, and in an auxiliary bearing in the upper part 15 of the compressor section. Oil is also thrown OK at various protruding points of the motor shaft, for example at the crank pin and the balance weight. In the present embodiment the cylinders and silencing chambers constitute a ring-shaped component 16 at the inner wall surface of which the discharged oil is intercepted. The oil runs downand collects in the motor-carrying element 6, above the stator 10.

In the face of the motor-carrying element '6 adjacent the stator, an orifice 18 is provided in the wall portion 17, and oil that has collected can drain off through this orifice. A wire 19 has been arranged in this orifice along which the oil can drain to a point immediately adjacent the sump. Alternatively, a plastic strip 20, indicated by dotted lines, is used which bears on the inner wall surface of the housing 2. Furthermore, a plastic thread 21 depends from the lower end of the stator and conducts oil draining off along the outer stator surface into sump. Obviously, a plurality of identical guide elements may be provided at different points of the circumference. These measures ensure that appreciable amounts of oil, which could produce dripping noises, are conducted silently to the sump 13.

I claim:

1. A sealed motor-compressor unit comprising a housing, a motor and a compressor disposed in said housing, an open oil sump in the bottom of said housing, means for distributing oil from said sump to various points in the interior of said housing, and at least one generally vertically hanging and flexible guide element attached at a strategic point in said housing to provide a gravity drain path externally of said element for the relatively silent return of oil to said sump.

2. A motor-compressor according to claim 1 said guide element extends from a draining point to a point immediately in the vicinity of said sump.

3. A motor-compressor according to claim 1 wherein said guide element extends from a draining point to an internal Wall surface of said housing from which oil can return reltively silently to said sump.

4. A motor-compressor according to claim 1, a stator casing for said motor, an orifice in said stator casing for draining oil from the inside to the outside of said casing, said guide element being attached in the vicinity of said orifice to provide at least a portion of an oil return path from said orifice to said sump.

5. A motor-compressor according to claim 1 wherein said guide element is a metal Wire or strip.

6. A motor-compressor according to claim 1 wherein said guide element is a plastic thread or band.

References Cited UNITED STATES PATENTS ROBERT M. WALKER, Primary Examiner US. Cl. X.R.