Linear motor and linear compressor

A linear motor comprising:

• prismatic inner yokes each formed by piling up a number of sheets each having a generally rectangular configuration and having a high magnetic permeability;
• outer yokes each formed by piling up a number of sheets each having a generally rectangular configuration and having a high magnetic permeability, each of said outer yokes having first and second slots formed by cutting in a piling-up direction of said sheets to establish first magnetic pole portion, a second magnetic pole portion and a third magnetic pole portion, with a surface of said outer yoke, holding said magnetic pole portions, being placed in an opposed relation to said inner yoke to define a predetermined gap therebetween to constitute each of a set of yoke blocks so that a magnetic path is established along surfaces of said sheets;
• coils each wound around said second magnetic pole portion for alternately establishing different magnetic poles in said first magnetic pole portion, said second magnetic pole portion and said third magnetic pole portion,
• a flat-plate-like base for holding said set of yoke blocks in a state where their inner yoke sides are placed in an opposed relation to each other to define a predetermined space;
• a bearing fitted to said base to be positioned between said inner yokes;
• a moving element including pairs of first and second lat-plate-like permanent magnets magnetized in directions of opposing of said inner yokes and said outer yokes and each placed within said gap in a state of being arranged at a predetermined interval along an axial direction of said bearing so that their magnetizing directions are opposite to each other, where, when said moving element shifts along said axial direction, said first flat-plate-like permanent magnet always crosses said first magnetic pole portion and said second magnetic pole portion while said second flat-plate-like permanent magnet always crosses said second magnetic pole and said third magnetic pole portion;
• and
• a shaft fitted integrally to said moving element and inserted into said bearing.

A linear motor comprising:

• prismatic inner yokes each formed by piling up a number of sheets each having a generally rectangular configuration and having a high magnetic permeability;
• outer yokes each formed by piling up a number of sheets each having a generally rectangular configuration and having a high magnetic permeability, each of said outer yokes including a plurality of slots formed by cutting said outer yoke in a sheets piling-up direction to establish a plurality of magnetic pole portions;
• coils respectively wound around all said magnetic pole portions other than said magnetic pole portions positioned at both ends of said outer yoke and made to alternately establish different magnetic poles in the adjacent magnetic pole portions;
• a set of yoke blocks each composed of said inner yoke, said outer yoke and said coils and each made such that a surface of said outer yoke, holding said magnetic pole portions, is placed at a predetermined gap in an opposed relation to said inner yoke to allow formation of a magnetic path along surfaces of said sheets;
• a flat-plate-like base for holding said set of yoke blocks in a state where their inner yoke sides are located in an opposed relation to each other to define a predetermined space;
• a bearing fitted to said base to be between said inner yokes of said set of yoke blocks;
• a moving element in which each of sets of flat-plate-like permanent magnets equal in number to said slots and magnetized in directions of facing of said inner yoke and said outer yoke are placed within a gap between said inner yoke and said outer yoke in a state of being arranged at a predetermined interval along an axial direction of said bearing so that their magnetizing directions are opposite to each other, where, when said moving element shifts along said axial direction, each of said flat-plate-like permanent magnets always crosses said adjacent magnetic pole portions of said outer yoke at the same time;
• and
• a shaft fitted integrally to said moving element and inserted into said bearing.

A linear motor according to this embodiment comprising:

• prismatic inner yokes each formed by piling up a number of sheets each having a generally rectangular configuration and having a high magnetic permeability;
• outer yokes each formed by piling up a number of sheets each having a generally rectangular configuration and having a high magnetic permeability, where a plurality of slots are formed by cutting the outer yoke in sheets piling-up direction to establish a plurality of magnetic pole portions;
• coils respectively wound around all the even-number magnetic pole portions of said plurality of magnetic pole portions and made to alternately establish different magnetic poles in the adjacent magnetic pole portions;
• a set of yoke blocks each including said inner yoke, said outer yoke and said coils and each made such that a surface of the outer yoke, holding said plurality of magnetic pole portions, is placed at a predetermined gap in an opposed relation to said inner yoke to allow formation of a magnetic path along surfaces of said sheets;
• a flat-plate-like base for holding said set of yoke blocks in a state where their inner yoke sides are located in an opposed relation to each other to define a predetermined space;
• a bearing fitted to said base to be between said inner yokes of said set of yoke blocks
• a moving element in which each of sets of flat-plate-like permanent magnets equal in number to said slots and magnetized in directions of facing of said inner yoke and said outer yoke are placed within a gap between said inner yoke and said outer yoke in a state of being arranged at a predetermined interval along an axial direction of said bearing so that their magnetizing directions are opposite to each other, where, when said moving element shifts along said axial direction, each of said flat-plate-like permanent magnets always crosses the adjacent magnetic pole portions of said outer yoke at the same time;
• and
• a shaft fitted integrally to said moving element and inserted into said bearing.

A linear compressor comprising:

• prismatic inner yokes each formed by piling up a large number of sheets each having a high magnetic permeability;
• outer yokes formed by piling up a large number of sheets each having a high magnetic permeability, where two slots are made in sheets piling-up directions to establish three magnetic pole portions therein;
• coils each wound around the central magnetic pole portion of said three magnetic pole portions of said outer yoke for alternately establishing different magnetic poles in said three magnetic pole portions;
• a set of yoke blocks each including said inner yoke and said outer yoke and made such that a surface of said outer yoke, carrying said magnetic pole portions, is placed in an opposed relation to said inner yoke to define a predetermined gap therebetween;
• a flat-plate-like base for holding the yoke blocks so that their inner yoke sides are in an opposed relation to each other to produce a predetermined space therebetween;
• a cylinder attached to said base to be positioned between said inner yokes;
• a moving element including pairs of flat-plate-like permanent magnets magnetized in opposing directions of said inner yokes and said outer yokes and located within said gaps between said inner yokes and said outer yokes in a state of being disposed to define a predetermined interval therebetween so that their magnetization directions are opposite to each other;
• a piston placed on a tip portion of a shaft constructed integrally with said moving element and inserted into said cylinder;
• and
• a spring connected to said shaft.