Abstract:
A compressor with internal noise abatement. The pulsations inherent in the cyclic compression and expansion of the gas in a piston-actuated compressor create acoustic energy that produces unwanted noise. Those pulsations are damped in a single unique tapered muffler chamber internal to the compressor.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This patent claims priority from and incorporates by reference the provisional U.S. Patent Application Ser. No. 60/785,895 filed by the same sole inventor on Mar. 24, 2006. 
     
    
       [0002]    The present invention relates to the field of compressors commonly used in vehicle air conditioning systems. Such systems can benefit from noise abatement features, commonly referred to as mufflers. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]      FIG. 1  is a front (proximate to bulkhead  2  and shaft end  25 ) to rear (proximate to bulkhead  3 ) cross section view of a compressor incorporating the preferred embodiment of the present invention. 
           [0004]      FIG. 2  is a transverse cross section view of a compressor cylinder block incorporating the preferred embodiment of the present invention. 
           [0005]      FIG. 3  is a transverse cross section view of a compressor cylinder block that mates with the cylinder block of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0006]    The structure and operation of the invention will become apparent upon reading the following detailed description of the preferred embodiment and upon reference to the accompanying drawings. The inventor presents herein the best mode for carrying out the present invention in terms of its preferred embodiment, depicted within the aforementioned drawings. 
         [0007]      FIG. 1  shows the preferred embodiment  15  of the present invention muffler chamber incorporated in compressor  100 . Compressor  100 , described in Publication No. US-2006-0165537-A1 (U.S. patent application Ser. No. 11/123,512) is one example of the type of compressor that can benefit from the present invention. In  FIG. 1  it can be seen that cylinder blocks  1  are assembled between front bulkhead  2  and rear bulkhead  3  with one or more fasteners such as bolts  30 . Within the interior cavities of cylinder blocks  1  is at least one piston  8  and swash plate  9 . In operation a drive belt, chain, gear, or other transfer means transfers some type of engine or motor energy to splined end  25  of shaft  12 . Shaft  12  rotational motion is imparted to the attached swash plate  9 . As angled swash plate  9  rotates, pistons  8  are forced to move up and down (if oriented with the longitudinal axis vertical) or fore and aft (if oriented with the longitudinal axis horizontal) within their respective cylinders or bores. The rotational motion of swash plate  9  thus converts the rotational motion of shaft  12  into linear reciprocating motion of pistons  8 . 
         [0008]    Commonly understood thermodynamic cooling cycles include stages of compression and expansion of a refrigerant gas, and the reciprocating motion of pistons  8  provides the required compression. At the end of the compression stage, the pressure of the compressed gas forces valves, such as valve  7  in  FIG. 1 , to open, thus providing routes by which the gas can escape the compression chambers and flow to the expansion part of the system where the desired cooling of an object or a space is achieved. 
         [0009]    In addition to noise created by the mechanical motion of pistons and valves, acoustic energy is produced by the pressure fluctuations of the refrigerant gas as it moves from a compression chamber to the expansion section of a cooling system. Ikeda addressed the issue of gas pressure fluctuation noise in U.S. Pat. No. 5,899,670. Ikeda claims a muffler consisting of two chambers, a large volume chamber and a small volume chamber, communicating with each other. Pulsations in the compressed gas are reflected inside the muffler chambers. The reflected pulses interfere with each other and are therefore attenuated before the gas is discharged into the external cooling circuit. The result is a diminution of noise inducing vibrations in the compressor and in the cooling circuit. The present invention offers the same noise abatement with a single tapered muffler chamber  15  built into cylinder blocks  1 . 
         [0010]    One part of the single tapered muffler chamber, cavity  10  in  FIG. 2 , is milled or cast into the front housing of a compressor. The other part of the muffler chamber, cavity  20  in  FIG. 3 , is milled or cast into the rear housing of a compressor. The complete muffler chamber  15 , made of mating cavities  10  and  20 , is formed when the front and rear housings are assembled. Passages  18  and  19  incorporated into the front and rear housings communicate with the assembled muffler chamber  15  and provide conduits for ingress and egress of gas into and out of muffler chamber  15 . 
         [0011]    Alternatively, a muffler cavity can be milled or cast into a housing component and made into a muffler chamber by closing it with a sealing plate or lid. In such a configuration passages  18  and/or  19  could be incorporated into the housing or into the plate or lid. Alternatively, using techniques such as selective laser sintering, sterolithography, or casting, a seamless muffler chamber can be formed integral to a housing component. 
         [0012]    In compressor  100  at least one conduit permits gas to flow from a compression chamber into the large end of the single tapered muffler chamber  15 . And at least one conduit permits gas to flow out of the small end of the single tapered muffler chamber  15  into the external cooling circuit of the cooling system serviced by compressor  100 . Alternatively, the direction of gas flow through the muffler chamber could be from the small end to the large end; noise abatement is achieved in either case. 
         [0013]    It will be apparent to those with ordinary skill in the relevant art having the benefit of this disclosure that the present invention provides an apparatus for compressor noise abatement. It is understood that the form of the invention shown and described in the detailed description and the drawings is to be taken merely as the presently preferred embodiment, and that the invention is limited only by the language of the claims. The drawings and detailed description presented herein are not intended to limit the invention to the particular embodiment disclosed. While the present invention has been described in terms of one preferred embodiment and a few alternative embodiments, it will be apparent to those skilled in the art that form and detail modifications can be made to those embodiments without departing from the spirit or scope of the invention.