Motor/generator phase insulation article and method for manufacturing

Apparatus including a monolithic, motor/generator phase insulation article having a manufactured state and a ready-to-use state. The insulation article has longitudinally-spaced-apart first and second tabs and flexible, transversely-spaced-apart first and second legs each having a first end monolithically joined to the first tab and a second end monolithically joined to the second tab. The first and second tabs are disposed longitudinally closer together in the manufactured state than in the ready-to-use state. In the manufactured state the first and second legs each have a more serpentine shape, and in the ready-to-use state the first and second legs each have a less serpentine shape. A method for manufacturing the insulation article is also described which cuts a monolithic, substantially-rectangular sheet of motor/generator phase insulation to create the insulation article.

TECHNICAL FIELD

The present invention relates generally to single or multi-phase electric motors and generators, and more particularly to a motor/generator phase insulation article and to a method for manufacturing a motor/generator phase insulation article.

BACKGROUND OF THE INVENTION

Conventional multi-phase electric motors include those having stator slots for phase coils and having monolithic, motor phase insulation articles each providing electrical insulation between corresponding adjacent phase coils at the two ends of the stator. In use, the thin motor phase insulation article has two tabs each positioned proximate a corresponding end of the stator between two sets of different phase coils. The two tabs are monolithically joined together by at least two legs each positioned in a corresponding one of the stator slots. The at-least-two legs monolithically hold the tabs together so the tabs do not fall off the stator or misalign during or after motor assembly.

A conventional method for manufacturing a motor phase insulation article includes obtaining a sheet of insulation, such as a rectangular sheet of Nomex® electrical insulation available from DuPont Corporation. The sheet is cut to remove material between adjacent legs and material outward from the outer two legs. It is noted that the insulation article is also known as an “H” paper insulator divider which provides a dielectric to separate stator windings.

Another conventional method for manufacturing a motor phase insulation article is disclosed in U.S. Pat. No. 5,093,543 whoseFIG. 5shows how an uninstalled motor phase insulation article is to be installed with its two legs each positioned in a corresponding stator slot of a multi-phase motor and which shows several installed motor phase insulation articles. In U.S. Pat. No. 5,093,543, the manufacturing method starts with a monolithic, non-rectangular, special-shaped sheet of insulation which includes steps along two of its eight edges and which includes two monolithically-abutting tabs. Three slits are then cut in the sheet of insulation to form the two legs and allow the tabs to be pulled apart for the motor phase insulation article to be ready to use.

What is needed is an improved motor/generator phase insulation article and an improved method for manufacturing a motor/generator phase insulation article.

SUMMARY OF THE INVENTION

An expression of an embodiment of the invention is for apparatus including a monolithic, motor/generator phase insulation article having a manufactured state and a ready-to-use state. The insulation article has a central longitudinal axis, has longitudinally-spaced-apart first and second tabs, and has flexible, transversely-spaced-apart first and second legs. The first and second legs each have a first end monolithically joined to the first tab and a second end monolithically joined to the second tab. The first and second tabs are positioned longitudinally closer together in the manufactured state than in the ready-to-use state. In the manufactured state the first and second legs each have a more serpentine shape, and in the ready-to-use state, the first and second legs each have a less serpentine shape.

A method of the invention is for manufacturing a motor/generator phase insulation article and includes steps a) and b). Step a) includes obtaining a monolithic, substantially-rectangular sheet of motor/generator phase insulation. Step b) includes cutting the sheet to remove material from the sheet, wherein the cut sheet has: (1) a central longitudinal axis; (2) longitudinally-spaced-apart first and second tabs; and (3) flexible, transversely-spaced-apart first and second legs each having a first end monolithically joined to the first tab and a second end monolithically joined to the second tab, wherein the first and second legs each have a serpentine shape.

Several benefits and advantages are derived from the expression of an embodiment and/or the method of the invention. In one example, a motor/generator phase insulation article is cut from a rectangular sheet of motor/generator phase insulation with a reduced amount of sheet wastage. In the same or a different example, the first and second legs of the manufactured motor/generator phase insulation article can be extended from a more serpentine manufactured state to a less serpentine, longitudinally extended shape for a first ready-to-use state for a first electric motor having a shorter stator stack length and can be further extended to an even less serpentine, more longitudinally extended shape for a second ready-to-use state for a second electric motor having a longer stator stack length.

DETAILED DESCRIPTION

Referring now to the drawings,FIGS. 1-2show an embodiment of the present invention. A first expression of the embodiment ofFIGS. 1-2is for apparatus10including a monolithic, motor/generator phase insulation article12having a manufactured state (as shown inFIG. 1) and a ready-to-use state (an example of which is shown inFIG. 2). The insulation article12has a central longitudinal axis14, has longitudinally-spaced-apart first and second tabs16and18, and has flexible, transversely-spaced-apart first and second legs20and22. The first and second legs20and22each have a first end24monolithically joined to the first tab16and a second end26monolithically joined to the second tab18. The first and second tabs16and18are positioned longitudinally closer together in the manufactured state (as shown inFIG. 1) than in the ready-to-use state (an example of which is shown inFIG. 2). In the manufactured state the first and second legs20and22each have a more serpentine shape, and in the ready-to-use state the first and second legs20and22each have a less serpentine shape.

As seen fromFIGS. 1-2, the first and second tabs16and18are spaced longitudinally further apart in the ready-to-use state than in the manufactured state. It is noted that the central longitudinal axis14is defined as an axis which passes through the center of one of the tabs16and18, which extends to the other of the tabs16and18, and which would pass through the center of the other tab if the other tab was identical in size and shape to the one tab. It is further noted that the central longitudinal axis14has been defined regardless of the width of the tabs16and18in relation to their spaced-apart longitudinal distance in the manufactured state and/or in the ready-to-use state.

In a first application, the insulation article12is a motor phase insulation article for a multi-phase or a single-phase electric motor, and in one employment, the legs20and22in the ready-to-use state are each disposed in a corresponding stator slot of the motor stator with the tabs16and18each extending beyond a corresponding stator end. In one variation the motor stator surrounds the motor rotor, and in another variation the motor rotor surrounds the motor stator. In a second application, the insulation article12is a generator phase insulation article for a multi-phase or a single-phase electric generator, and in one employment, the legs20and22in the ready-to-use state are each disposed in a corresponding stator slot of the generator stator with the tabs16and18each extending beyond a corresponding stator end. In one variation the generator stator surrounds the generator armature, and in another variation the generator armature surrounds the generator stator. In one choice of material, the insulation article12consists essentially of Nomex® electrical insulation available from DuPont Corporation. Other choices of material are left to those skilled in the art.

In one enablement of the first expression of the embodiment ofFIGS. 1-2, the first and second tabs16and18each are substantially bisected by the central longitudinal axis14, and the central longitudinal axis14is disposed substantially transversely-midway between the first and second legs20and22. In one extension of the first expression of the embodiment ofFIGS. 1-2, the insulation article12includes at least one additional, flexible leg (not shown) monolithically connecting the first and second tabs16and18, having a more serpentine shape in the manufactured state, and having a less serpentine shape in the ready-to-use state. In one variation, in the manufactured state the first and second tabs16and18and the first and second legs20and22lie substantially in a common plane. In one modification, the first and second tabs16and18are flexible.

In one implementation of the first expression of the embodiment ofFIGS. 1-2, in the manufactured state the first and second legs20and22each have a plurality of substantially straight and substantially longitudinally-aligned leg segments28. In one variation, in the manufactured state the first leg20has a plurality of first leg turns30, the second leg22has a plurality of second leg turns32, the leg segments28of the first leg20are monolithically joined together in serial-flow relationship by the first leg turns30, and the leg segments28of the second leg22are monolithically joined together in serial-flow relationship by the second leg turns32. It is noted that the leg turns30and32may be curved (as shown inFIG. 1) or straight. In one modification, in the manufactured state the leg segments28of the first leg20include a multiplicity of upper leg segments34extending from proximate the first tab16to proximate longitudinally-midway to the second tab18, a multiplicity of lower leg segments36extending from proximate the second tab18to proximate longitudinally-midway to the first tab16, and a connecting leg segment38extending from proximate the first tab16to proximate the second tab18. It is noted that the term “proximate” includes, but is not limited to, “at”. In one arrangement, the connecting leg segment38is disposed transversely outward from the upper and lower leg segments34and36. In one illustration, in the ready-to-use state at least one leg segment28of the first leg20is bent over or under a monolithically-joining first leg turn30to increase the longitudinal extent of the first leg20.

In one construction, in the manufactured state the second leg22is a substantially mirror image of the first leg20about the central longitudinal axis14. In one variation, in the manufactured state the second tab18is a substantially mirror image of the first tab16about the central longitudinal axis14. In one example, such mirror images also exist in the ready-to-use state.

A method of the invention is for manufacturing a motor/generator phase insulation article12and includes steps a) and b). Step a) is labeled in block40ofFIG. 3as “Obtain Rectangular Sheet Of Motor/Generator Phase Insulation”. Step a) includes obtaining a monolithic, substantially-rectangular sheet of motor/generator phase insulation. Step b) is labeled in block42ofFIG. 3as “Cut Sheet To Create Tabs And Legs”. Step b) includes cutting the sheet to remove material from the sheet, wherein the cut sheet has: (1) a central longitudinal axis; (2) longitudinally-spaced-apart first and second tabs; and (3) flexible, transversely-spaced-apart first and second legs each having a first end monolithically joined to the first tab and a second end monolithically joined to the second tab, wherein the first and second legs each have a serpentine shape.

In one employment of the method, the sheet is placed between top and bottom cutting dies, and the top and bottom cutting dies are brought into engagement to cut the sheet to create the insulation article12. Other employments of the method, including the use of a laser cutting machine, are left to the artisan. In one example, the sheet is 8.25 inches long, 7.00 inches wide, and 0.007 inches thick. In this example, the cut sheet would create a manufactured insulation article12(such as that shown inFIG. 1) having identical first and second tabs16and18which are spaced 2.248 inches apart with each tab being 7.000 inches wide and 3.000 inches long (with length measured along the central longitudinal axis14) and having mirror image first and second legs20and22transversely spaced 1.750 inches apart with each leg having nine leg segments28each 0.125 inches wide. In the ready-to-use state of greatest longitudinal separation of the first and second tabs16and18, the first and second tabs would be substantially 9 inches apart.

In one enablement of the method, step b) cuts the sheet with the first and second tabs16and18each substantially bisected by the central longitudinal axis14and with the central longitudinal axis14disposed substantially transversely-midway between the first and second legs20and22. In one variation, step b) cuts the sheet with the first and second tabs16and18and the first and second legs20and22lying substantially in a common plane.

In one implementation of the method, step b) cuts the sheet with the first and second legs20and22each having a plurality of substantially straight and substantially longitudinally-aligned leg segments28. In one variation, step b) cuts the sheet with the first leg20having a plurality of first leg turns30, with the second leg22having a plurality of second leg turns32, with the leg segments28of the first leg20monolithically joined together in serial-flow relationship by the first leg turns30, and with the leg segments28of the second leg22monolithically joined together in serial-flow relationship by the second leg turns32. In one modification, step b) cuts the sheet with the leg segments28of the first leg20including a multiplicity of upper leg segments34extending from proximate the first tab16to proximate longitudinally-midway to the second tab18, a multiplicity of lower leg segments36extending from proximate the second tab18to proximate longitudinally-midway to the first tab16, and a connecting leg segment38extending from proximate the first tab16to proximate the second tab18. In one arrangement, step b) cuts the sheet with the connecting leg segment38disposed transversely outward from the upper and lower leg segments34and36.

In one extension, the method is also for preparing the manufactured motor/generator phase insulation article12for use, and also includes step c). Step c) is labeled in block44ofFIG. 3as “Bend At Least One Leg Segment To Define A First Ready-To-Use State For a First Electric Motor Having A First Stator Stack Length”. Step c) includes bending at least one leg segment28of the first leg20over or under a monolithically-joining first leg turn30to increase the longitudinal extent of the first leg20and partially define a first ready-to-use state of the motor/generator phase insulation article12for a first electric motor/generator having a first stator stack length. In a further extension, the method also includes step d). Step d) is labeled in block46ofFIG. 3as “Bend At Least One More Leg Segment To Define A Second Ready-To-Use State For a Second Electric Motor Having A Second Stator Stack Length”. Step d) includes bending at least one more leg segment28of the first leg20over or under a monolithically-joining first leg turn30to further increase the longitudinal extent of the first leg20and partially define a second ready-to-use state for a second electric motor/generator having a second stator stack length which is greater than the first stator stack length of the first electric motor/generator.

In one enactment of the method, step b) cuts the sheet with the second leg22a substantially mirror image of the first leg20about the central longitudinal axis14. In one variation, step b) cuts the sheet with the second tab18a substantially mirror image of the first tab16about the central longitudinal axis14.

FIG. 4shows a first alternate embodiment of a motor/generator phase insulation article112of the invention, wherein the first and second legs120and122each are monolithically joined to the first and second tabs116and118. In this embodiment, the first and second legs120and122each transversely-outwardly flow in a serpentine manner but transversely-inwardly return in a non-serpentine manner whereas, in the embodiment ofFIG. 1, the first and second legs20and22each transversely-outwardly flow and transversely-inwardly return in a serpentine manner. It is noted that the previous description given in paragraph [0015] of the first expression of the embodiment ofFIGS. 1-2also describes the first alternate embodiment of the insulation article112ofFIG. 4.

FIG. 5shows a second alternate embodiment of a motor/generator phase insulation article212of the invention, wherein the first and second legs220and222each are monolithically joined to the first and second tabs216and218. In this embodiment, the first and second legs220and222each longitudinally flow in a serpentine manner whereas, in the embodiment ofFIG. 1, the first and second legs20and22transversely flow in a serpentine manner. It is noted that the previous description given in paragraph [0015] of the first expression of the embodiment ofFIGS. 1-2also describes the second alternate embodiment of the insulation article212ofFIG. 5. Other alternate embodiments are left to those skilled in the art.

Several benefits and advantages are derived from the expression of an embodiment and/or the method of the invention. In one example, a motor/generator phase insulation article is cut from a rectangular sheet of motor/generator phase insulation with a reduced amount of sheet wastage. In the same or a different example, the first and second legs of the manufactured motor/generator phase insulation article can be extended from a more serpentine manufactured state to a less serpentine, longitudinally extended shape for a first ready-to-use state for a first electric motor having a shorter stator stack length and can be further extended to an even less serpentine, more longitudinally extended shape for a second ready-to-use state for a second electric motor having a longer stator stack length.