Metal working – Plural diverse manufacturing apparatus including means for... – Separate tool stations for selective or successive operation...
Reexamination Certificate
1999-09-30
2001-09-04
Hall, Carl E. (Department: 3729)
Metal working
Plural diverse manufacturing apparatus including means for...
Separate tool stations for selective or successive operation...
C029S564800, C029S596000, C029S734000, C493S949000
Reexamination Certificate
active
06282773
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to the manufacture of electromechanical machines, such as electric motors. More particularly, the invention relates to an improved method and apparatus for producing slot insulators and inserting same into the stator core of an electromechanical machine.
Electric motors and other electromechanical machines are generally constructed having a cylindrical stator core. The inner circumference of the stator core defines a plurality of radial slots in which electrical windings are maintained. A slot insulator, typically referred to as a “slot liner,” is located on the inner circumferential surface of each winding slot in order to electrically isolate the windings from the stator core.
During the manufacturing process, individual slot liners are typically inserted into the respective winding slots using automated equipment designed for this purpose. The slot liners themselves have been formed from a roll of insulator material having a width dictated by the axial length of the stator core in which the slot liners are to be inserted. To form individual slot liners, a quantity of material is first drawn from the roll. The material is then cut to a length equivalent to the inner circumferential portion of the winding slot to be insulated. End cuffs are passively formed along the sides of the insulator material as it is pulled from the roll.
For example, consider a stator core having an axial length of 5″ and in which each winding slot has an inner circumferential portion of 1.5″ to be insulated. According to the prior art described above, it is necessary to use a roll of insulator material having a width of greater than 5″ in order to produce slot liners for this core. The insulator material is drawn from the roll, and cut into 1.5″ lengths. The insulator blank formed in this manner is bent into a U-shaped slot liner and moved axially into a respective slot.
Typically, a face plate is utilized for slot liner insertion. The face plate defines a plurality of guides in the pattern of the stator core's winding slots. The guides are maintained in register with the end of the stator core as it is indexed to receive the next slot liner.
While the prior art has worked generally well to achieve the formation and insertion of slot liners, it is not without disadvantages. For example, multiple stator lengths may be offered within a single motor size. Thus, it is necessary to maintain in stock rolls of each width that will be required to produce slot liners for all of the various stator lengths.
In addition, the face plate used for slot liner insertion is a relatively complex and expensive part. Moreover, the face plate has a tendency to “grip” the slot liners, often causing the slot liners to be pulled partially from the slots as the stator core is removed from the face plate. When this happens, the slot liners must be manually reinserted into the winding slots.
SUMMARY OF THE INVENTION
The present invention recognizes and addresses the foregoing disadvantages, and others, of prior art constructions and methods. Accordingly, it is an object of the present invention to provide novel methodology for the production of winding slot insulators.
It is a more particular object of the present invention to provide novel methodology by which winding slot insulators may be produced from an elongate strip of insulator material.
It is also an object of the present invention to provide a novel apparatus for the production of winding slot insulators.
It is a further object of the present invention to provide a novel apparatus for the insertion of winding slot insulators.
Some of these objects are achieved by a method of forming and inserting a winding slot insulator in a winding slot defined in a stator core. The method involves providing an elongate strip of slot insulator material having a predetermined width equivalent to an inner circumferential portion of the winding slot to be insulated. Based on the axial length of the stator core, a predetermined length of the slot insulator material is separated from the strip to provide an insulator blank. The insulator blank is formed into a U-shaped slot insulator and inserted into a selected winding slot of the stator core.
The method may further comprise the step of forming cuffs at both axial ends of the insulator blank before the U-shaped slot insulator is formed. For example, the cuffs may be formed at a trailing end of the insulator blank and a leading end of the remaining elongate strip. According to exemplary methodology, the cuffs may be produced by vertically-moving cuff pushers operating adjacent to a cutting blade.
Preferably, the U-shaped slot insulator is inserted axially into the selected winding slot through a guide element presenting a reduced dimension guideway. Often, it will be desirable to move the guide element to a location adjacent to the selected winding slot prior to insertion of the U-shaped slot insulator.
Other objects of the present invention are achieved by an apparatus for forming and inserting a winding slot insulator in a winding slot defined in a stator core. The apparatus comprises a reel support adapted to maintain a reel of slot insulator material having a predetermined width. A feed mechanism is operative to deliver a quantity of the slot insulator material from the reel to a cutting station.
The apparatus includes a cutting mechanism located at the cutting station. The cutting mechanism is operative to cut through the slot insulator material to provide an insulator blank having cuffs at respective ends thereto. The insulator blank is received in a die mechanism operative to form the insulator blank into a U-shaped slot insulator. A transfer mechanism is operative to insert the U-shaped slot insulator into the winding slot.
In some exemplary embodiments, the cutting mechanism includes a cutting blade having first and second cuff pushers located on each side thereof. The cuff pushers are operative to form a respective cuff on a trailing end of the insulator blank and a leading end of the quantity of insulator material. Often, the cutting blade and the cuff pushers will be operative to move together from opposite sides of the insulator material.
The apparatus may further comprise a retractable guide element movable to an operative position adjacent to the winding slot to present a reduced dimension guideway through which the U-shaped slot insulator is inserted. Often, the guideway of the retractable guide element may be formed by plural components that converge together as the guide element is moved into the operative position.
Preferably, the die mechanism will be situated in longitudinal alignment with the cutting station for receipt of the insulator blank therein. In such cases, the die mechanism may be operative to move laterally from a first position aligned with the cutting station to a second position aligned with the winding slot.
Still further objects of the present invention are achieved by an apparatus for forming and inserting a winding slot insulator in a winding slot defined in a stator core. The apparatus comprises a feed mechanism operative to deliver a quantity of slot insulator material to a cutting station. A cutting mechanism is located at the cutting station, and is operative to cut through the slot insulator material to provide an insulator blank having a predetermined length. The insulator blank is received in a die mechanism operative to form the insulator blank into a U-shaped slot insulator. A transfer mechanism is operative to insert the U-shaped slot insulator into the winding slot. A retractable guide element, movable to an operative position adjacent to the winding slot, is also provided. The guide element presents a reduced dimension guideway through which the U-shaped slot insulator is inserted.
Additional objects of the present invention are achieved by an apparatus for forming a cuffed insulator blank from an elongate strip of insulator material. The apparatus comprises a reel support adapted to mainta
Gerasimow Alexander M.
Hall Carl E.
Killen Craig N.
Rockwell Technologies LLC
Walburn William R.
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