Linear compressor

The present invention relates to linear compressors, and in particular linear compressors of the type suitable for use in a vapour compression refrigeration system.

Linear compressors of a type for use in a vapour compression refrigeration system are the subject of many documents in the prior art. One such document is our co-pending PCT patent application PCT/NZ2004/000108. That specification describes a variety of developments relating to such compressors, many of which have particular application to the linear compressors. The present invention relates to further improvements to compressor embodiments such as are described in that patent application which provides a general exemplification of a compressor to which the present invention may be applied. However the present may also be applied beyond the scope of the particular embodiments of a linear compressor disclosed in that application. Persons skilled in the art will appreciate the general application of the ideas herein to other embodiments of linear compressors such as are found in the prior art.

It is an object of the present invention to provide improvements relating to linear compressors or to at least provide the industry with a useful choice.

In a first aspect the invention may broadly be said to consist in a linear compressor comprising:

a cylinder part including a cylinder bore,

a piston disposed in said bore and slidable therein,

a main spring connecting directly or indirectly said cylinder part to said piston,

a connecting member connecting between said main spring and said piston,

a stator having an air gap, said connecting member passing through said air gap, and

one or more substantially flat blocks of permanent magnet material secured to said connecting member with the large faces of said blocks facing the stator, said permanent magnet material magnetised to define at least one armature pole; and wherein said main spring comprises a combination of a plurality of individual spring elements acting in parallel.

In a further aspect the invention may broadly be said to consist in a linear compressor comprising:

a cylinder part including a cylinder bore,

a piston disposed in said bore and slidable therein,

a main spring connecting directly or indirectly said cylinder part to said piston,

a connecting member connecting between said main spring and said piston,

a stator having an air gap, said connecting member passing through said air gap, and

at least one armature pole located along said connecting member,

wherein said connecting member is supported only by said piston at one end and by said main spring away from said one end, and said main spring comprises a combination of individual spring elements acting in parallel.

In a still further aspect the invention may broadly be said to consist in a linear compressor comprising:

a cylinder part including a cylinder bore,