Refrigerant compressor with rotation detecting means

A refrigerant compressor comprising:

• a housing assembly formed by a plurality of framework members combined together;
• a mechanical combining means for mechanically combining said plurality of framework members in a fluid-tight condition;
• a drive shaft rotatably supported in said housing assembly and having a drive portion thereof within said housing assembly, and an axial extension outwardly extending from said drive portion thereof so as to receive a drive power from an external drive source via a solenoid clutch having a stator element containing a solenoid;
• a compressing means mounted on said drive portion of said drive shaft within said housing assembly for performing a repetitive motion upon being driven by said drive shaft to compress a refrigerant gas;
• and
• a rotation detecting means which comprises in combination:
• a magnetic circuit means for permitting magnetic flux leaking from said solenoid clutch to circulatively flow through said drive shaft, said compressing means, and said mechanical combining means;
• a magnetic detecting means arranged in said magnetic circuit means in a region outside said housing assembly for detecting a change in the magnetic flux which occurs in response to the repetitive motion of said compressing means to thereby produce an output signal representing a rotating speed of said compressor;
• and
• a permanent magnet means fixedly arranged in one of said plurality of framework members at a position close to said magnetic detecting means and where said permanent magnet means confronts said compressing means, said permanent magnet means being arranged to generate an additional magnetic flux increasing the density of the magnetic flux circulating through said magnetic circuit means at a position close to said magnetic detecting means to thereby activate the detecting operation of said magnetic detecting means.