Rotary compressor

Abstract

The eccentric on the crankshaft of a rotary compressor, as well as the roller that surrounds the crankshaft, is replaced by an elliptical cam that acts as a double eccentric. In this manner, the elliptical cam provides for proper balancing of the crankshaft and other components of the compressor, while eliminating the need to use counterweights. Specifically, the elliptical cam is symmetrical, resulting in equal forces acting on opposing sides of the elliptical cam. This allows the elliptical cam to maintain its balance throughout its rotation, even when operating at a high rate of revolution.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit under Title 35, U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 61 / 246,319, filed Sep. 28, 2009, titled ROTARY COMPRESSOR, the disclosure of which is expressly incorporated herein by reference.BACKGROUND[0002]1. Field of the Invention[0003]The present invention relates to compressors and, particularly, to rotary compressors.[0004]2. Description of the Related Art[0005]In a rotary compressor, the compression mechanism includes an eccentric positioned within a cylindrical compression chamber. A vane extending from the cylindrical wall of the compression chamber contacts a roller positioned around the eccentric and divides the compression chamber into compression and suction pockets. As the eccentric and, correspondingly, the roller move through the compression chamber, the compression pocket decreases in volume to compress a working fluid contained therein. At the same time, the suction pock...

AI Technical Summary

Benefits of technology

[0007]The present invention relates to compressors and, particularly, to rotary compressors. In one exemplary embodiment, the eccentric on the crankshaft of a rotary compressor, as well as the roller that surrounds the eccentric, is replaced by an elongated, preferably elliptical, cam that acts as a double eccentric. In this manner, the elliptical cam provides for inherent balancing of the crankshaft and other components of the compressor, eliminating the need to use counterweights. Specifically, the elliptical cam is symmetrical, resulting in equal inertial forces acting on opposing sides of the elliptical cam. This allows the elliptical cam to maintain its balance throughout its rotation, even when operating at a high rate of revolution. Additionally, because pressure forces from the compression pockets are equal and opposite in direction, bearing loads are reduced which allows for the use of a smaller bearing. This, in turn, reduces the viscous frictional losses associated with shearing of oil in the bearings, which increases mechanical efficiency.

[0008]Advantageously, eliminating the use of counterweights in the rotary compressor of the present invention decreases the overall height and size of the compressor. Additionally, it allows for the rotary compressor to be utilized to compress larger volumes of working fluid and also eliminates the need to provide a roller surrounding an eccentric on the crankshaft.

[0010]Additionally, in one exemplary embodiment, the outboard journal bearing is eliminated and the crankshaft of the compressor includes only a single journal bearing, i.e., the main bearing, which is positioned between the cylinder and the motor. Elimination of the outboard journal reduces the viscous friction losses of the compressor and increases mechanical efficiency. Also, because the outboard journal consists of precisely machined surfaces, its elimination reduces the cost of manufacturing the compressor.

Problems solved by technology

However, as the size of the rotary compressor increases, the size of the eccentric and its corresponding counterweight also increase.

As a result, the size of the counterweights make both the design and assembly of such a compressor increasingly difficult.

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