Coil spool with protrusion to prevent wire migration

Abstract

A wire holding device for, e.g., a coil used in a vehicle sensor, actuator, or ignition has a spool defining a winding bay that is bounded by opposed flanges of the spool. A wire support extends from flange to flange to define a winding surface, and a wire coil is wound in turns in the bay around the wire support. One or more protrusions are formed on the wire support and protrude above the winding surface for impeding lateral displacement of wires in the first layer of turns that lies against the surface of the wire support.

1 . A wire holding device, comprising: 
 a spool defining a winding bay, the winding bay being bounded by opposed flanges of the spool, a wire support extending from flange to flange and defining a winding surface;    a wire coil wound in turns in the bay around the wire support; and    at least one protrusion formed on the wire support and protruding above the surface thereof for impeding lateral displacement of wires at least in a first layer of turns that lies against the surface of the wire support, wherein no portion of a wire is disposed radially inwardly from the surface of the wire support.    
   
   
       2 . The device of  claim 1 , wherein the height of the protrusion above the surface of the winding bay is approximately one-third the diameter of a wire in the coil.  
   
   
       3 . The device of  claim 1 , wherein the distance from one of the flanges and the at least one protrusion is an integer “N” number of coil turns, wherein “N” is established at least in part based on a desired threshold lateral movement amount and a wire diameter variance.  
   
   
       4 . The device of  claim 1 , comprising plural protrusions on the wire support and spaced longitudinally thereon, wherein the number and spacing of protrusions is at least in part based on a desired threshold lateral movement amount and a wire diameter variance.  
   
   
       5 . The device of  claim 1 , wherein the protrusion extends only part way around the wire support so that the next turn of wire may alter course and lay flat without without crossing on top of the protrusion.  
   
   
       6 . The device of  claim 3 , wherein the threshold lateral movement amount is about one-half the nominal diameter of a wire in the coil.  
   
   
       7 . A wire holding device, comprising: 
 a spool including a winding surface;    a wire coil wound in turns around the winding surface; and    at least one protrusion formed on the winding surface for impeding lateral displacement of wires at least in a first layer of turns that lies against the winding surface, wherein the number and spacing of protrusions at least in part is based on a desired threshold lateral movement amount and a wire diameter variance.    
   
   
       8 . The device of  claim 7 , wherein no portion of a wire is disposed radially inwardly from the surface.  
   
   
       9 . The device of  claim 7 , wherein the height of the protrusion above the surface is approximately one-third the diameter of a wire in the coil.  
   
   
       10 . The device of  claim 7 , comprising plural protrusions on the wire support and spaced longitudinally thereon.  
   
   
       11 . The device of  claim 7 , wherein the protrusion extends only part way around the wire support so that the next turn of wire may alter course and lay flat without without crossing on top of the protrusion.  
   
   
       12 . The device of  claim 7 , wherein the threshold lateral movement amount is about one-half the nominal diameter of a wire in the coil.  
   
   
       13 . A spool for holding a coil of wire, comprising: 
 a wire support extending between two flanges and having at least one protrusion formed on a surface thereof.    
   
   
       14 . The spool of  claim 13 , comprising a wire coil wound in turns around the surface, wherein the number and spacing of protrusions at least in part is based on a desired threshold lateral movement amount and a wire diameter variance.  
   
   
       15 . The spool of  claim 13 , wherein no portion of a wire is disposed radially inwardly from the surface.  
   
   
       16 . The spool of  claim 14 , wherein the height of the protrusion above the surface is approximately one-third the diameter of a wire in the coil.  
   
   
       17 . The spool of  claim 13 , comprising plural protrusions on the wire support and spaced longitudinally thereon.  
   
   
       18 . The spool of  claim 14 , wherein the protrusion extends only part way around the wire support so that the next turn of wire may alter course and lay flat without without crossing on top of the protrusion.  
   
   
       19 . The spool of  claim 14 , wherein the threshold lateral movement amount is about one-half the nominal diameter of a wire in the coil.