Stator, associated electric motor and associated method

An electric motor with a stator includes a first plurality of coils and a plurality of first electrical connectors. Each of the coils of the first plurality of coils are connected to at least one of the plurality of first electrical connectors. The stator also includes a first guide on a first end of the motor for guiding each of the first electrical connectors. The stator also includes a second plurality of coils. Each of the coils of the second plurality coils is connected to at least one of a plurality of second electrical connectors. The stator also includes a second guide on a opposed second end of the motor positioned at least partially over the second end face of the stator. The second guide guides each of the second electrical connectors.

BACKGROUND

The field of the disclosure relates generally to electric motors, and more specifically, three phase electric motors with interpole connections.

Three phase electric motors, including EC motors have winding systems that are wound with multiple coils on the stator core that must be connected together, hereafter referred to as interpole connections. These motors are often wound in such a way that results in the interpole connections of each phase to be in contact with each other. This can lead to winding failures if the phases short together. For ease of manufacturing, these interpole connections are typically routed around the outside edge of the stator core and on the same end of the stator. The wires can be routed using features of an insulating stator endcap. This leads to the interpole connections crossing over each other in multiple locations, creating a risk of phase-to-phase shorts due to the voltage potential difference between the phases.

Much effort has been taken over the years to improve insulation properties of the windings. There are many different methods used to keep the interpole connections electrically isolated from each other, but most require complex parts, extra labor, or specialized manufacturing equipment. The invention presented here involves winding the three phase motors by moving one of the three phase interpole connections to the opposite side of the stator core as the other two phases. By electrically isolating one of the phases, it reduces the number of opportunities for phase-to-phase shorts by at least ⅓. As an example, the winding pattern presented below reduces the number of phase-to-phase contact points from 9 to 3. Another benefit of this invention is that it allows use of larger diameter wire without having to increase the thickness or height of the insulating end cap design.

BRIEF DESCRIPTION

According to an aspect of the present invention, an electric machine is provided. The machine includes a housing that defines a cavity in the housing. The housing has an external periphery. The machine also includes a rotor and a stator.

The rotor defines an axis of rotation of the rotor. The rotor is disposed at least partially within the housing and configured to rotate relative to the housing about the axis of rotation

The stator is positioned at least partially within the housing. The stator includes a body connected to the housing. The body defines a plurality of spaced apart inwardly extending protrusions. The protrusions extend axially in a direction parallel to the axis of rotation of the rotor from a first end face of the stator to an opposed second end face of the stator. The stator also includes a first plurality of coils. Each of the coils of the first plurality coils is wrapped around one of the protrusions.

The stator also includes a plurality of first electrical connectors. Each of the coils of the first plurality of coils are connected to at least one of the plurality of first electrical connectors. The stator also includes a first guide positioned at least partially over the first end face of the stator. The first guide guides each of the first electrical connectors.

The stator also includes a second plurality of coils. Each of the coils of the second plurality coils are wrapped around one of the protrusions. The stator also includes a plurality of second electrical connectors. Each of the coils of the second plurality coils is connected to at least one of the plurality of second electrical connectors. The stator also includes a second guide positioned at least partially over the second end face of the stator. The second guide guiding each of the second electrical connectors.

In another aspect, the machine may be configured wherein the first guide defines a feature for receiving a portion of at least one of the plurality of first electrical connectors.

In another aspect, the machine may be configured wherein the first guide is made of a polymer.

In another aspect, the machine may be configured wherein the electric machine includes a three phase electrically commutated motor.

In another aspect, the machine may be configured wherein the first plurality of coils is utilized for a first of the three phases of the motor.

In another aspect, the machine may be configured wherein the second plurality of coils is utilized for one of a second and a third of the three phases of the motor.

In another aspect, the machine may be configured wherein the plurality of first electrical connectors include connector wires.

In another aspect, the machine may be configured wherein the first plurality of coils includes coil wires.

In another aspect, the machine may be configured wherein at least one of the coil wires and at least one of the connector wires are fabricated of a continuous wire.

In another aspect, the machine may be configured wherein the protrusions include teeth.

In another aspect, the machine may be configured wherein at least one of the first guide and the second guide includes tooth portions of the guides, each tooth portion positioned adjacent one of the teeth.

In another aspect, the machine may be configured wherein at least one of the first plurality of coils and second first plurality of coils is wrapped around one of the tooth portions.

In another aspect, the machine may be configured wherein the first guide includes axially extending tabs for guiding the plurality of first electrical connectors.

In another aspect, the machine may be configured wherein the first guide defines a circumferential recess for guiding the plurality of first electrical connectors.

According to another aspect of the present invention, a stator is provided. The stator is for use in an electric machine having a housing and a rotor. The rotor defines an axis of rotation of the rotor. The stator is positioned at least partially within the housing.

The stator includes a body connected to the housing, the body defining a plurality of spaced apart inwardly extending protrusions. The protrusions extend axially in a direction parallel to the axis of rotation of the rotor from a first end face of the stator to an opposed second end face of the stator. The stator also includes a first plurality of coils. Each of the coils of the first plurality coils are wrapped around one of the protrusions. The stator also includes a plurality of first electrical connectors. Each of the coils of the first plurality coils are connected to at least one of the plurality of first electrical connectors.

The stator also includes a first guide positioned at least partially over the first end face of the stator. The first guide guides each of the first electrical connectors.

The stator also includes a second plurality of coils. Each of the coils of the second plurality coils wrapped around one of the protrusions.

The stator also includes a plurality of second electrical connectors. Each of the coils of the second plurality of coils is connected to at least one of the plurality of second electrical connectors.

The stator also includes a second guide positioned at least partially over the second end face of the stator. The second guide guides each of the second electrical connectors.

In another aspect, the stator may be configured wherein the first guide defines a feature for receiving a portion of at least one of the plurality of first electrical connectors.

In another aspect, the stator may be configured wherein the first guide includes a polymer.

In another aspect, the stator may be configured wherein the electric machine includes a three phase electrically commutated motor.

In another aspect, the stator may be configured wherein the first plurality of coils is utilized for a first of the three phases of the motor.

In another aspect, the stator may be configured wherein the second plurality of coils is utilized for one of a second and a third of the three phases of the motor.

In another aspect, the stator may be configured wherein the plurality of first electrical connectors include connector wires.

In another aspect, the stator may be configured wherein the first plurality of coils include coil wires.

In another aspect, the stator may be configured wherein at least one of the coil wires and at least one of the connector wires are fabricated of a continuous wire.

In another aspect, the stator may be configured wherein the protrusions include teeth.

In another aspect, the stator may be configured wherein at least one of the first guide and the second guide includes tooth portions. Each tooth portion may be positioned adjacent one of the teeth.

In another aspect, the stator may be configured wherein at least one of the first plurality of coils and second first plurality of coils is wrapped around one of the tooth portions.

In another aspect, the stator may be configured wherein the first guide includes axially extending tabs for guiding the plurality of first electrical connectors.

In another aspect, the stator may be configured wherein the first guide defines a circumferential recess for guiding the plurality of first electrical connectors.

According to another aspect of the present invention, a method for making an electrical machine is provided. The method includes the step of providing a housing defining a cavity therein and having an external periphery of the housing. The method also includes the step of providing a rotor defining an axis of rotation of the rotor and the step of disposing the rotor at least partially within the housing. The method also includes the step of configuring the rotor to rotate relative to the housing about the axis of rotation and the step of providing a stator with a first end face and an opposed second end face.

The method also includes the step of positioning the stator at least partially within the housing. The stator includes a body. The method also includes the step of connecting the body to the housing and the step of providing the body with a plurality of spaced apart inwardly extending protrusions. The method also includes the step of extending the protrusions in a direction parallel to the axis of rotation of the rotor from the first end face of the stator to the opposed second end face of the stator and the step of positioning a first guide at least partially over the first end face of the stator.

The method also includes the step of positioning a second guide at least partially over the second end face of the stator and the step of wrapping wire around one of the protrusions to form a first coil. The method also includes the step of wrapping wire around another one of the protrusions to form a second coil and the step of connecting the first coil to a first electrical connector. The method also includes the step of connecting the second coil to a second electrical connector and the step of wrapping wire around another one of the protrusions to form a third coil.

The method also includes the steps of wrapping wire around another one of the protrusions to form a fourth coil, connecting the third coil to a third electrical connector, connecting the fourth coil to a fourth electrical connector, and guiding the third electrical connector and the fourth electrical connector along the second guide.

In another aspect, the method may be provided wherein the electric machine includes a three phase electrically commutated motor. The method may further include the step of utilizing the first plurality of coils for a first of the three phases of the motor and further include the step of utilizing the second plurality of coils for one of a second and a third of the three phases of the motor.

DETAILED DESCRIPTION

Referring toFIG. 1and according to an aspect of the present invention, an electric machine10is provided. As shown, the machine10is a motor. It should be appreciated that the machine10may also be a generator. The machine10includes a housing12that defines a cavity14in the housing12. The housing12has an external periphery16. The machine10also includes a rotor18and a stator20.

The rotor18defines an axis of rotation22of the rotor18. The rotor18is disposed at least partially within the housing12and configured to rotate relative to the housing12about the axis of rotation22.

The stator20is positioned at least partially within the housing12. The stator20includes a body24having a central opening21for receiving the rotor18and the stator20is connected to the housing12. The body24may have any suitable shape and be made of any suitable materials. For example, to obtain proper electromagnetic properties, the body24may be made of a series of planar sheets of, for example, metal. The sheets may be joined together mechanically or by an adhesive.

Referring now toFIGS. 2-6, the stator20is shown in greater detail. The body24of the stator20defines a plurality of spaced apart inwardly extending protrusions or teeth26. The protrusions26extend axially in a direction parallel to the axis of rotation of the rotor18from a first end face28of the stator20to an opposed second end face30of the stator body24. The stator20also includes a first plurality31of coils32formed from wire33, typically a continuous wire. Each of the coils32of the first plurality of coils is wrapped around one of the protrusions26.

As shown inFIG. 4, the stator20also includes a plurality of first electrical connectors34. As shown, the first plurality31of coils32are shown in solid lines. Each of the coils32of the first plurality31of coils are connected to at least one of the plurality of first electrical connectors34. The stator20also includes a first guide36positioned at least partially over the first end face28of the stator20, the first guide36guiding each of the first electrical connectors34.

For a three-phase motor, as shown inFIGS. 2-6, one third of the coils are wired to be energized by each of the three phases: phase A, phase B and phase C. For example, for a 15-coil motor, 5 coils are energized by each phase. As shown, for a 12-coil motor, 4 coils are energized by each phase. The first plurality31of coils32may represent phase A or the blue coil leads.

Referring now toFIG. 5, the stator20also includes a second plurality38of coils, each of the coils32of the second plurality38of coils is wrapped around one of the teeth26. The stator20also includes a plurality of second electrical connectors40.

As shown, the first plurality38of coils32are shown in dotted lines. Each of the coils32of the second plurality38of coils is connected to at least one of the plurality of second electrical connectors40. The stator20also includes a second guide42positioned at least partially over the second end face30of the stator20. The second guide42guides each of the second electrical connectors40. For a three-phase motor, as shown inFIGS. 2-6, the second plurality38of coils32may represent phase C.

It should be appreciated that the guides36and42may guide the electrical connectors34and40in any suitable way, may have any suitable shape, and may be made of any suitable material or materials. For example, the guides36and42may be in the form of a cover or end plate that fits over the end faces28and30of the stator20. For example, the guides36and42may define a first feature44for receiving a portion45of at least one of the plurality of first electrical connectors34and40.

The first feature44may, as shown inFIG. 2, be in the form of a tab or finger extending radially outwardly from body46of guides36and42. The tab44may, as shown inFIG. 2, be in the form of a protrusion, tab or finger and may have a uniform cross section, for example, a rectangular cross section. The tab44may, as shown be integral with the body46of the guides36and42.

It should be appreciated that the guides36and42may be made of a suitable durable material, for example a polymer, a metal or a composite. As shown the guides36and42may be made of a polymer and may be molded.

The guides36and42may, as shown, for simplicity and to minimize costs, be identical to each other. The guides36and42may be mirror images of each other and may be different in shape, size, construction or materials.

As shown inFIGS. 2-6, the body46of the guides36and42may have a generally planar disk shape that defines an outer cylindrical ring41, an inner cylindrical ring43and a plurality of spokes47extending from the outer ring41to the inner ring43. The spokes47and the rings41and43define openings49bounded by the spokes47and the rings41and43. The openings49provide passageways for the wire33that forms the coils32. For simplicity, the openings49and the teeth26have a one to one correspondence and the openings49are aligned with the spaces27between teeth26where the coils32are formed.

The guides36and42may also include peripheral voids51. For example, the voids may be in the form of rectangular voids51B with a semicircular end for passage of housing longitudinal fasteners or bolts17used to connect first end cap13to the second end cap15and to secure the stator body or laminations24to the housing12(seeFIG. 1).

As shown inFIGS. 4 and 5, the voids51extend axially through the guides36and42. For example, the voids51may likewise be in the form of semicircular voids51A that may provide a passageway for wires between the stator20and the housing12.

As shown inFIGS. 3-6, the guides36and42may also include the tabs44to provide support and guidance for the connectors31that extend from the coils32to power supply or power source48. One tab44may be aligned with each opening49and extend axially from the outer cylindrical ring41. Additional tabs44may be positioned in alignment with the rectangular voids51B.

As shown inFIG. 6, it should be appreciated that the connectors34and40conduct electricity from the power source48to the coils32. The connectors34and40may run directly from the power source48to a coil or from one coil32to another coil32.

When building a motor, a motor builder or a winding machine advances continuous wire33around a tooth26to form a coil32and then forms a portion of the first connector34as the wire is advanced along the outside face of the guide. In this process the wire33passes along the outside face of the guide several times and, depending on the coils that are wired together, may both add a complex pattern of wire on the outside face of the guide that makes the thickness of the stator increase and makes the winding operation of the motor more difficult. Also, some the paths required for the wire may make abrupt turns that may undesirable.

Typically, a winding machine includes a needle that has a wire holder in the form of for example an opening or hole. The needle enters the stator20from the central opening21of the stator20and guides the wire33around the teeth26. For simplicity, wire conservation and winding efficiency the wire is guided along the outer face of the guide from the first tooth to have a coil wound about it to the next tooth to have a coil wound about it

The arrangement of the connectors may vary widely depending on the type of motor. For example, the motor may be a capacitive start induction motor that has start windings that include a first plurality of coils that are connected to each other by the first connectors and a second plurality of coils that are connected to each other by the second connectors.

As shown inFIGS. 2-4, The first connectors may be positioned along the outside face of the first guide as the first plurality of coils are wound about the teeth. Similarly, the second connectors may be positioned along the second guide as the second plurality of coils are wound about the teeth. The tabs44serve to keep the connections in a proper position. By positioning the first connectors on the first guide and the second connectors on the second guide, the wiring of the motor may be simplified, resulting in shorter wire paths and reduced manufacturing and materials cost.

As shown, the motor, as stated above, may be an ECM motor with—3—three sets of windings, each set for a different one of three separate phases i.e. energized by each of the three phases: phase A, phase B and phase C. The problems mentioned above regarding capacitive start induction motors with start windings and run windings, particularly those related to connections and leads, are complicated by having a third set of winding in addition to the two sets of winding of an induction motor.

The ECM motor10ofFIGS. 1-6has the first plurality31of coils32or first set of coils that are connected to each other by the first connectors34, a second plurality38of coils34or second set of coils that are connected to each other by the second connectors40and, as shown inFIGS. 3-6, a third plurality50of coils32or third set of coils that are connected to each other by third connectors52.

As discussed earlier, to simplify wire winding paths and to minimize wire length, each of the three sets of windings should be formed by having the wire guided along the outer faces of only one guides of the stator from each tooth to have a coil wound about it to the next tooth to have a coil wound about it.

Since the ECM motor has three sets of winding, for simplicity and efficiency, two sets of windings should be formed by having the wire guided along the outer faces of the first guide of the stator and the third set of windings should be formed by having the wire guided along the outer faces of the second guide of the stator, or vice versa.

The first connectors may be positioned along the outside face of the first guide as the first plurality of coils are wound about the teeth. Similarly, the second connectors may be positioned along the second guide as the second plurality of coils are wound about the teeth. The tabs44serve to keep the connections in a proper position. By positioning the first connectors on the first guide and the second connectors on the second guide, the wiring of the motor may be simplified, resulting in shorter simpler wire paths and reduced manufacturing and materials cost.

Referring again toFIGS. 4 and 5, the first guide36, the first plurality31of coils, the third plurality50of coils, the first electrical connectors34and the third electrical connectors52are shown in greater detail. It should be appreciated that the motor10may be configured such that the each spoke or tooth portion47of the first guide is aligned with one of the teeth26of the body24of the stator20. As shown, the motor10may also be configured wherein the wires33of the coils32are wrapped around the tooth portions47of the first guide36. The tooth portions47of the first guide36include an edge or corner54that protects the wire33as it is wound around the first guide36and the teeth26.

As shown, the motor10may also be configured wherein the first guide36includes the axially extending tabs44for guiding the plurality of first electrical connectors34and for guiding the plurality of third electrical connectors52.

As shown, the motor10may also be configured wherein the first guide36defines a circumferential recess56formed in outer face58of the outer ring41for guiding the plurality of first electrical connectors34and for guiding the plurality of third electrical connectors52.

The recess56and the tabs44serve to separate the wires33, particularly those of different phases, and to minimize current leakage between phases and to the stator body26.

Referring now toFIGS. 2-6, the second guide42, the second plurality38of coils, and the second electrical connectors40are shown in greater detail. It should be appreciated that the motor10may be configured such that the each spoke or tooth portion47of the first guide is aligned with one of the teeth26of the body24of the stator20. As shown, the motor10may also be configured wherein the wires33of the coils32are wrapped around the tooth portions47of the second guide42. The tooth portions47of the second guide42include an edge or corner54that protects the wire33as it is wound around the second guide42and the teeth26.

As shown, the motor10may also be configured wherein the second guide42includes the axially extending tabs44for guiding the plurality of second electrical connectors38.

As shown, the motor10may also be configured wherein the second guide42defines a circumferential recess56formed in outer face58of the outer ring41for guiding the plurality of second electrical connectors38.

The recess56and the tabs44, as well as placing second electrical connectors40for the second plurality38of coils on the second end face30of the stator20, separated from the first electrical connectors34for the first plurality31of coils and the third electrical connectors52for the third plurality50of coils on the first end face28of the stator20, serve to separate the wires33, particularly those of different phases, and to minimize current leakage between phases and to the stator body26.

Referring now toFIG. 8and according to another aspect of the present invention, a method100for making an electrical machine is provided. The method100includes step110of providing a housing defining a cavity therein and having an external periphery of the housing. The method100also includes step112of providing a rotor defining an axis of rotation of the rotor and step114of disposing the rotor at least partially within the housing. The method also includes step116of configuring the rotor to rotate relative to the housing about the axis of rotation and step118of providing a stator with a first end face and an opposed second end face.

The method also includes step120of positioning the stator at least partially within the housing. The stator includes a body. The method also includes step122of connecting the body to the housing and step124of providing the body with a plurality of spaced apart inwardly extending protrusions. The method also includes step126of extending the protrusions in a direction parallel to the axis of rotation of the rotor from the first end face of the stator to the opposed second end face of the stator and step128of positioning a first guide at least partially over the first end face of the stator.

The method also includes step130of positioning a second guide at least partially over the second end face of the stator and step132of wrapping wire around one of the protrusions to form a first coil. The method also includes step134of wrapping wire around another one of the protrusions to form a second coil and step136of connecting the first coil to a first electrical connector. The method also includes step138of connecting the second coil to a second electrical connector and step140of wrapping wire around another one of the of the protrusions to form a third coil.

The method also includes step142of wrapping wire around another one of the protrusions to form a fourth coil, step144of connecting the third coil to a third electrical connector, step146of connecting the fourth coil to a fourth electrical connector, and step148of guiding the third electrical connector and the fourth electrical connector along the second guide.

In another aspect, the method may be provided wherein the electric machine includes a three phase electrically commutated motor. The method may further include the step of utilizing the first plurality of coils for a first of the three phases of the motor and further include the step of utilizing the second plurality of coils for one of a second and a third of the three phases of the motor.

The apparatus, methods, and systems described herein provide an electric motor and a stator assembly of the electric motor. The stator assembly is configured to provide an electric motor that may be used in additional applications to reduce inventory and simplify repair and replacement. For example, embodiments of the stator assembly include winding that provide a first or lower speed and a second or higher speed. In addition, in some embodiments, provide for wiring harnesses that simplify the installation of the motor. As a result, the motor may be used for multiple applications and reduce inventory and related costs.

Exemplary embodiments of an electric motor assembly are described above in detail. The electric motor assembly and its components are not limited to the specific embodiments described herein, but rather, components of the systems may be utilized independently and separately from other components described herein. For example, the components may also be used in combination with other machine systems, methods, and apparatuses, and are not limited to practice with only the systems and apparatus as described herein. Rather, the exemplary embodiments can be implemented and utilized in connection with many other applications.