US4922604A — Method of fabricating an encapsulated motor

Claim 1

Independent Claim 143 words

A method of producing an electrical motor comprising the steps of: assembling a rotor assembly on a rotor shaft having a rotor section of predetermined diameter and bearings on the rotor shaft of slightly larger diameter than the rotor section; assembling a plurality of stator laminations, stator windings, terminations and stator end caps to form an assembled but uncompleted stator assembly; potting the assembled stator assembly to form a unitized potted stator assembly; machining a continuous bore through the center of the potted stator assembly to produce a concentric bore for the rotor section and mounting surfaces for the rotor bearings; and mounting the rotor assembly into the stator assembly, the mounting step including inserting the rotor assembly into the bore of the stator assembly with the bearings engaging the bearing mounting surfaces machined in the end caps during the bore forming step.

Claim 2

Independent Claim 143 words

A method of producing an electrical motor comprising the steps of: assembling a rotor assembly on a rotor shaft having a rotor section of predetermined diameter and bearings on the rotor shaft of slightly larger diameter than the rotor section; assembling a plurality of stator laminations, stator windings, terminations and stator end caps to form an assembled but uncompleted stator assembly; potting the assembled stator assembly to form a unitized potted stator assembly; machining a continuous bore through the center of the potted stator assembly to produce a concentric bore for the rotor section and mounting surfaces for the rotor bearings; and mounting the rotor assembly into the stator assembly, the mounting step including inserting the rotor assembly into the bore of the stator assembly with the bearings engaging the bearing mounting surfaces machined in the end caps during the bore forming step.

Claim 3

Dependent Claim 64 words

The method of claim 1 in which the assembling step comprises attaching a plurality of stator laminations together to form a lamination stack having clearance holes therethrough, and assembling the stator end caps and lamination stack by means of bolts passed through said clearance holes and clearance holes in at least one of the end caps to form the assembled but uncompleted stator assembly.

Claim 4

Dependent Claim 14 words

The method of claim 2 in which the stator laminations are attached by welding.

Claim 5

Dependent Claim 52 words

The method of claim 1 in which the assembling step comprises attaching a plurality of stator laminations together to form a lamination stack, and assembling the stator end caps and lamination stack by means of adhesive attaching the end caps to the lamination stack to form the assembled but uncompleted stator assembly.

Claim 6

Dependent Claim 15 words

The method of claim 2 in which the end caps are unmachined prior to assembly.

Claim 7

Dependent Claim 40 words

The method of claim 1 in which the potting step comprises injecting potting material into the end caps and stator laminations to form a smooth continuous bore through the stator assembly having all voids therein substantially filled with potting material.

Claim 8

Dependent Claim 83 words

The method of claim 6 in which one of the end caps has a pair of apertures registered with apertures through the laminations, and the potting step comprises inserting a needle through one of the end cap apertures and through the stator lamination stack, injecting potting material into the assembled stator assembly through the needle thereby to fill the stator assembly from the bottom up, and expelling air through the second end cap aperture as the assembled stator assembly fills with potting material.

Claim 9

Dependent Claim 74 words

The method of claim 7 in which the potting step further comprises inserting an arbor through the bore of the assembled but uncompleted stator assembly prior to potting said arbor engaging the end caps but being out of contact with the laminations, and the injecting of potting material serving to force potting material between the arbor and the stator laminations to cover the inner surface of the laminations and form said smooth continuous bore.

Claim 10

Dependent Claim 41 words

The method of claim 8 wherein the potting step further comprises heating the assembled but uncompleted stator assembly after insertion of the arbor to a degree sufficient to expand the arbor into contact with the inner surfaces of the end caps.

Claim 11

Dependent Claim 86 words

The method of claim 1 in which the stator laminations have a plurality of inwardly facing stator poles, each of the poles having a plurality of pole teeth separated by gaps, and in which the potting step comprises potting the stator assembly in such a way as to dispose potting material in the gaps between the stator teeth, and the bore forming step comprises machining a bore through the stator by removing both potting material and material from the stator teeth while forming said central bore.

Claim 12

Dependent Claim 104 words

The method of claim 10 in which the potting step further comprises inserting an arbor through a central opening in the end caps and laminations, and heating the assembled but uncompleted stator assembly with inserted arbor to a degree sufficient to cause said arbor to expand into contact with the inner surfaces of the end caps but leaving a gap between the arbor and the pole teeth, and injecting potting material into the stator assembly with inserted arbor so as to force potting material between the arbor and the pole teeth, thereby to fill all the gaps between the pole teeth with potting material.

Claim 13

Dependent Claim 74 words

The method of claim 11 in which one of the end caps has a pair of apertures registered with apertures through the laminations, and the potting step further comprises inserting a needle through one of the end cap apertures and through the apertures in the laminations, injecting potting material through the needle to fill the stator assembly with potting material from the bottom up while forcing air out of the second end cap aperture.

Claim 14

Dependent Claim 31 words

The method of claim 12 in which the bore forming step comprises lapping said bore to form the central bore for the rotor section and mounting surfaces for the rotor bearings.

Claim 15

Dependent Claim 13 words

The method of claim 13 in which the lapping step comprises diamond lapping.

Claim 16

Dependent Claim 31 words

The method of claim 12 in which the bore forming step comprises honing said bore to form the central bore for the rotor section and mounting surfaces for the rotor bearings.

Claim 17

Dependent Claim 31 words

The method of claim 12 in which the bore forming step comprises broaching said bore to form the central bore for the rotor section and mounting surfaces for the rotor bearings.

Claim 18

Dependent Claim 42 words

The method of claim 12 further including installing a connector in one of the end caps for terminating the stator windings in such a way as to prevent leakage of potting material in the area of the connector during the potting step.

Claim 19

Dependent Claim 49 words

The method of claim 12 further comprising the step of installing permanent magnets on the stator poles in the gaps between the stator teeth, and the potting step comprises covering the installed permanent magnets with potting material to assist in holding the magnets in place between the stator teeth.

Claim 20

Dependent Claim 39 words

The method of claim 18 in which the bore forming step comprises diamond lapping of the internal bore to remove potting material leaving exposed stator teeth and inserted permanent magnets held in place in the gaps by potting material.

Claim 21

Dependent Claim 55 words

The method of claim 1 in which the electrical motor is a hybrid permanent magnet stepping motor and in which the step of assembling the rotor comprises assembling at least two stacks of toothed rotor laminations separated by a permanent magnet with the teeth of the respective rotor lamination stacks being offset from each other.

Claim 22

Independent Claim 257 words

A method of manufacturing an electrical motor comprising the steps of: producing a rotor assembly including a rotor shaft carrying a plurality of rotor laminations stacked to form a rotor section, and assembling rotor bearings on the rotor shaft, the rotor bearings having an outer diameter which is slightly larger than the outer diameter of the rotor section; assembling a stator lamination stack by fixedly joining a plurality of stator laminations, the stator lamination stack having stator poles on the inside and an outer surface on the outside; forming a wound stator by assembling insulators and windings on the poles in the stator lamination stack; forming a capped stator assembly by assembling stator electrical termination means and a pair of end caps on the wound stator assembly, the end caps being assembled leaving exposed the outer surface of the stator lamination stack between the end caps; potting the capped stator assembly to form a potted stator assembly; machining a bore in the center of the potted stator assembly through the end caps and the stator lamination stack, the bore through the stator lamination stack forming a bore for rotation of the rotor section, and the bore through the end caps forming mounting surfaces for the rotor bearings; and inserting the rotor assembly into the bore of the stator assembly with the bearings at either end of the rotor assembly engaging the bearing mounting surfaces in the end caps with the rotor section intermediate, the mounting step including fixing the bearings in place in their respective end caps.

Claim 23

Independent Claim 257 words

A method of manufacturing an electrical motor comprising the steps of: producing a rotor assembly including a rotor shaft carrying a plurality of rotor laminations stacked to form a rotor section, and assembling rotor bearings on the rotor shaft, the rotor bearings having an outer diameter which is slightly larger than the outer diameter of the rotor section; assembling a stator lamination stack by fixedly joining a plurality of stator laminations, the stator lamination stack having stator poles on the inside and an outer surface on the outside; forming a wound stator by assembling insulators and windings on the poles in the stator lamination stack; forming a capped stator assembly by assembling stator electrical termination means and a pair of end caps on the wound stator assembly, the end caps being assembled leaving exposed the outer surface of the stator lamination stack between the end caps; potting the capped stator assembly to form a potted stator assembly; machining a bore in the center of the potted stator assembly through the end caps and the stator lamination stack, the bore through the stator lamination stack forming a bore for rotation of the rotor section, and the bore through the end caps forming mounting surfaces for the rotor bearings; and inserting the rotor assembly into the bore of the stator assembly with the bearings at either end of the rotor assembly engaging the bearing mounting surfaces in the end caps with the rotor section intermediate, the mounting step including fixing the bearings in place in their respective end caps.

Claim 24

Dependent Claim 64 words

The method of claim 21 in which the assembling step comprises welding a plurality of stator laminations together to form a lamination stack having clearance holes therethrough, and assembling the stator end caps and lamination stack by means of bolts passed through said clearance holes and clearance holes in at least one of the end caps to form a loosely registered capped stator assembly.

Claim 25

Dependent Claim 15 words

The method of claim 22 in which the end caps are unmachined prior to assembly.

Claim 26

Dependent Claim 36 words

The method of claim 21 in which the potting step comprises injecting potting compound into the end caps and stator laminations to form a bore through the stator assembly which is completely sealed by potting material.

Claim 27

Dependent Claim 84 words

The method of claim 21 in which the stator laminations have a plurality of inwardly facing stator poles, each of the poles having a plurality of pole teeth, and in which the potting step comprises potting the capped stator assembly in such a way as to dispose potting material in gaps between the stator teeth, and the machining step comprises machining a bore through the potted stator assembly by removing both potting material and material from the stator teeth while forming said central bore.

Claim 28

Dependent Claim 30 words

The method of claim 25 in which the machining step comprises lapping said bore to form the central bore for the rotor section and mounting surfaces for the rotor bearings.

Claim 29

Dependent Claim 13 words

The method of claim 26 in which the lapping step comprises diamond lapping.

Claim 30

Dependent Claim 46 words

The method of claim 25 further comprising the step of installing permanent magnets on the stator poles between the stator teeth, and the potting step comprises covering the installed permanent magnets with potting material to assist in holding the magnets in place between the stator teeth.

Claim 31

Dependent Claim 29 words

The method of claim 23 in which the machining step comprises diamond lapping of the internal bore to remove potting material leaving exposed stator teeth and inserted permanent magnets.

Claim 32

Dependent Claim 55 words

The method of claim 21 in which the electrical motor is a hybrid permanent magnet stepping motor and in which the step of assembling the rotor comprises assembling at least two stacks of toothed rotor laminations separated by a permanent magnet with the teeth of the respective rotor lamination stacks being offset from each other.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-05-07	1993-11-06	1994-05-08	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-05-07	1997-11-06	1998-05-08	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-05-07	2001-11-06	2002-05-08	$7700.00	Window Closed / Lapsed

Method of fabricating an encapsulated motor

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