Modular stator for tubular electric linear motor and method of manufacture

Abstract

A modular design for and method of constructing long stators for tubular electric linear motors having many sets of coils. In certain embodiments, the stator is made by assembling a multiplicity of identical coil modules which are combined to form a stator of whatever length may be required. In some embodiments, coil modules containing the coils are connected by intermediate connectors. In those embodiments, the sum of the effective length of the coil module and the effective length of the intermediate connector must be an integral multiple of the pole pitch of the magnets in the motor's mover. In some embodiments, longitudinal grooves are formed in the coil modules to provide paths for coolant.

What is claimed is: 
     
         1 . A stator for a tubular linear motor, comprising:
 a plurality of electrically interconnected identical coil modules, each coil module comprising a plurality of coils, a plurality of metal comb shaped elements, each of said comb shaped elements comprising a longitudinal spine and a plurality of teeth, whereby the longitudinal spines of said metal comb shaped elements are distributed about a circumference of the coils and the teeth are located between adjacent coils, and a set of externally accessible electrical connections at each end of each of said coil modules, and   a cylindrical housing surrounding said coil modules.   
     
     
         2 . The stator of  claim 1 , wherein each of said comb shaped elements has a laminated structure. 
     
     
         3 . The stator of  claim 1 , wherein said stator is powered by three phase current and the number of coils in the module is an integer multiple of three. 
     
     
         4 . The stator of claim  11 , further comprising a coolant path between the longitudinal spines of adjacent pairs of the comb shaped elements. 
     
     
         5 . A tubular linear motor, comprising:
 a stator including a plurality of electrically interconnected identical coil modules, each coil module comprising a plurality of coils, a plurality of metal comb shaped elements, each of said comb shaped elements comprising a longitudinal spine and a plurality of teeth, whereby the longitudinal spines of said metal comb shaped elements are distributed about a circumference of the coils and the teeth are located between adjacent coils, and a set of externally accessible electrical connections at each end of each of said coil modules, and a cylindrical housing surrounding said coil modules; and   a mover.   
     
     
         6 . A method for manufacturing a stator for a tubular linear motor, comprising:
 interconnecting a plurality of coil modules, each coil module comprising a plurality of coils, a plurality of metal comb shaped elements, each of said comb shaped elements comprising a longitudinal spine and a plurality of teeth, whereby the spines of said metal comb shaped elements are distributed about the circumference of the coils and the teeth are located between adjacent coils, and a set of externally accessible electrical connectors at each end of each of said coil modules, and   inserting said interconnected coil modules into a cylindrical housing.   
     
     
         7 . The method for manufacturing a stator for a tubular linear motor of  claim 6 , wherein said coil modules are interconnected by intermediate connectors which electrically connect a set of electrical connectors on one coil module with a corresponding set of electrical connectors on another coil module. 
     
     
         8 . A method for manufacturing a coil module for a stator for a tubular linear motor, comprising:
 placing a plurality of bobbins and spacers on a winding mandrel;   winding said plurality of bobbins with a single length of wire to form a set of coils;   interleaving three sets of said coils on an encapsulation mandrel;   distributing a plurality of metal comb shaped elements, each of said comb shaped elements comprising a longitudinal spine and a plurality of teeth, about the circumference of said interleaved sets of coils;   surrounding said interleaved sets of coils and said metal comb shaped elements with an encapsulation mold;   encapsulating said interleaved sets of coils and said metal comb shaped elements in an encapsulating material; and   removing the encapsulated coil module from said mold and said encapsulation mandrel after solidification of said encapsulating material.