Linear stepper motor and fixture for the magnetization of the shaft thereof and methods
AssigneeTri-Tech, Inc.
InventorRobert Pulford JR.
Life of this patent
Estimating the term…
Abstract
In a preferred embodiment, linear stepper motor, comprising; an annular stator structure; an axially extending, cylindrical, permanent magnet shaft extending coaxially through said annular stator structure; and the axially extending, cylindrical, permanent magnet shaft having a smooth external surface along a portion thereof with axially alternating N and S poles defined circumferentially in an outer periphery of the portion of the axially extending, cylindrical, permanent magnet shaft. The present invention also provides a method of magnetizing the shaft of such a motor and a fixture and method of manufacturing the fixture therefor.
Claims22
A linear stepper motor, comprising;
- (a) an annular stator structure;
- (b) an axially extending, cylindrical, permanent magnet shaft extending coaxially through said annular stator structure;
- and
- (c) said axially extending, cylindrical, permanent magnet shaft having a smooth external surface along a portion thereof with axially alternating n and s poles defined circumferentially in an outer periphery of said portion of said axially extending, cylindrical, smooth, permanent magnet shaft.
A fixture for magnetizing axially alternating N and S poles defined circumferentially in a portion of an outer periphery of an axially extending, cylindrical, smooth shaft, said fixture comprising:
- (a) a hollow cylindrical mandrel formed from a non-magnetic, non-electrically-conducting material;
- (b) a conductive wire disposed in parallel, circumferential channels defined in an outer surface of said mandrel;
- (c) a potting compound surrounding said mandrel to secure said conductive wire in place;
- and
- (d) a central bore defined axially and centrally through said mandrel and exposing or nearly exposing said conductive wire;
- and
- (e) said central bore being sized to accept axially inserted therein said portion of said axially extending, cylindrical, smooth shaft.
A method of providing axially alternating N and S poles in a portion of an axially extending, cylindrical, smooth shaft for a linear stepper motor, comprising:
- (a) providing a magnetizing fixture comprising:
- a hollow cylindrical mandrel formed from a non-magnetic material;
- a conductive wire disposed in parallel, circumferential channels defined in an outer surface of said mandrel;
- a potting compound surrounding said mandrel to secure said conductive wire in place;
- and a central bore defined axially and centrally through said mandrel and exposing or nearly exposing said conductive wire;
- and said central bore being sized to accept axially inserted therein said portion of said axially extending, cylindrical, smooth shaft;
- (b) inserting said portion of said axially extending, cylindrical shaft in said central bore;
- and
- (c) providing a direct current through said conductive wire said conductive wire is placed in said parallel, circumferential channels such that direction of flow in said conductive wire of a direct current in adjacent ones of said parallel, circumferential channels is in opposite directions.
A method of manufacturing a magnetizing fixture for magnetizing axially alternating N and S poles defined circumferentially in a portion of an outer periphery of an axially extending, cylindrical, smooth shaft, said method comprising:
- (a) providing a plurality of parallel, circumferential channels defined in an outer surface of a cylindrical mandrel formed from a non-magnetic material;
- (b) placing a conductive wire in said parallel, circumferential channels;
- (c) providing a potting compound surrounding said mandrel to secure said conductive wire in place;
- (d) forming a central bore defined axially and centrally through said mandrel and exposing or nearly exposing said conductive wire;
- and
- (e) said central bore being sized to accept axially inserted therein said portion of said axially extending, cylindrical, smooth shaft.
Dependencies are inferred from the claim text.