Motor endshield promoting controller air cooling

A motor assembly for powering a fluid blower includes a stator, a rotor rotatable relative to the stator about an axis of rotation, and an inner shell. The inner shell includes axially opposite first and second shell ends and encloses, at least in part, the stator and the rotor. An outer housing at least partly surrounds the inner shell such that an axially extending fluid channel is defined between the inner shell and the outer housing. A motor controller is positioned within the outer housing and is configured to control at least one operational parameter of the motor assembly. Furthermore, the motor assembly includes a flow-directing endshield located within the outer housing and adjacent the first shell end. The rotor is supported, at least in part, by the flow-directing endshield. The flow-directing endshield is fluidly interposed between the fluid channel and motor controller and is configured to direct a fluid flow between the fluid channel and the motor controller.

BACKGROUND

The embodiments described herein relate generally to an electric machine, and more particularly, to a motor assembly for powering a fluid blower where a fluid flow is used to cool the motor controller.

Electric motors are used in a variety of applications, including, for example, appliances (e.g., exercise bicycles, rowing machines, ceiling fans, dishwashers, washing machines, and vacuum cleaners) and vehicles (e.g., cars, trucks, and golf carts). Such motors typically include a control system that generates heat and/or is subjected to undesirably high environmental temperatures. It is therefore desirable in some instances to provide means for cooling at least some of the components of the control system.

SUMMARY

In one aspect, a motor assembly for powering a fluid blower is provided. The motor assembly includes a stator, a rotor rotatable relative to the stator about an axis of rotation; and an inner shell presenting axially opposite first and second shell ends and enclosing, at least in part, the stator and rotor. The motor assembly also includes an outer housing at least partly surrounding the inner shell such that an axially extending fluid channel is defined therebetween. A motor controller is positioned within the outer housing and configured to control at least one operational parameter of the motor assembly. A flow-directing endshield is located within the outer housing adjacent the first shell end, with the rotor being at least in part supported by the flow-directing endshield. The flow-directing endshield is fluidly interposed between the fluid channel and the controller. Furthermore, the flow-directing endshield is configured to direct a fluid flow between the fluid channel and the controller.

Advantages of these and other embodiments will become more apparent to those skilled in the art from the following description of the exemplary embodiments which have been shown and described by way of illustration. As will be realized, the present embodiments described herein may be capable of other and different embodiments, and their details are capable of modification in various respects. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.

Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of this disclosure. These features are believed to be applicable in a wide variety of systems comprising one or more embodiments of this disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein. While the drawings do not necessarily provide exact dimensions or tolerances for the illustrated components or structures, the drawings are to scale with respect to the relationships between the components of the structures illustrated in the drawings.

DETAILED DESCRIPTION

The following detailed description of embodiments of the disclosure references the accompanying figures. The embodiments are intended to describe aspects of the disclosure in sufficient detail to enable those with ordinary skill in the art to practice the disclosure. The embodiments of the disclosure are illustrated by way of example and not by way of limitation. Other embodiments may be utilized, and changes may be made, without departing from the scope of the claims. The following description is, therefore, not limiting. The scope of the present disclosure is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled.

In the following specification and the claims, reference will be made to several terms, which shall be defined to have the following meanings. The singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

As used herein, the terms “axial” and “axially” refer to directions and orientations extending substantially parallel to a longitudinal or rotational axis of the motor assembly. The terms “radial” and “radially” refer to directions and orientations extending substantially perpendicular to the rotation axis. The terms “tangent” and “tangential” refer to the directions and orientations extending substantially perpendicular to a radial direction of the motor assembly. In addition, as used herein, the terms “circumferential” and “circumferentially” refer to directions and orientations extending in the general direction around the rotation axis of the motor assembly (such references not being limited to pure circular extension or to the periphery or outer perimeter of the object unless the context clearly indicates otherwise). Moreover, directional references, such as, “top,” “bottom,” “front,” “back,” “side,” and similar terms are used herein solely for convenience and should be understood only in relation to each other. For example, a component might in practice be oriented such that faces referred to herein as “top” and “bottom” are in practice sideways, angled, inverted, etc. relative to the chosen frame of reference.

Example Electric Machine

FIG. 1is an exploded perspective view of an exemplary electric machine10, in accordance with one aspect of the present invention.FIG. 2is a sectional view of a housing assembly70of the electric machine10. In the exemplary embodiment, the electric machine10is a vacuum cleaner for use in a vehicle (preferably, a vacuum cleaner for use in an automobile), although use of the electric machine10in alternative applications and/or machines is contemplated with respect to certain aspects of the present invention.

In the exemplary embodiment, the electric machine10includes a motor assembly12coupled to a fluid blower14. In an example embodiment, the blower includes, for example, a multi-stage blower having a plurality of blower wheels (not shown), each housed in respective stage housings (not shown). In other example embodiments, it is contemplated that any type of blower that enables the electric machine10to function as described herein may be used.

The motor assembly12is operable to rotate the blower14to generate a fluid flow. More particularly, as described in detail below, as the blower14is rotated by motor assembly12, the blower14generates an exhaust fluid flow (preferably, a stream of air) directed toward the motor assembly12. Alternatively, in certain aspects of the present invention, the fluid flow orientation of the motor assembly12relative to the blower14could be reversed, for example, where the motor assembly12is coupled to the intake side of the blower14.

The motor assembly12broadly includes a stator16and a rotor18substantially enclosed within an inner shell20. The rotor18is rotatable about an axis of rotation “A.” In a preferred embodiment, the stator16at least substantially circumscribes the rotor18, such that the motor assembly12is an inner rotor motor. An inner rotor motor preferably has magnets (not shown) positioned radially inward relative to the stator16. However, according to other aspects of the present invention, the rotor and stator may alternately be constructed as an outer rotor motor and/or a dual rotor motor. In addition, the motor assembly12may be constructed for use in an electric generator or other electric machine that comprises a stator and rotor.

The stator16is generally toroidal in form and defines a stator axis that is coaxial with the axis of rotation “A.” However, according to some aspects of the present invention, it is permissible for the axes to be non-coaxial.

The stator16preferably includes a stator core22and a plurality of coils (not shown) wound about the stator core22. Furthermore, the stator16includes a plurality of electrically insulative coverings24positioned between the stator core22and the coils.

The stator core22preferably is fabricated from steel and may be of either solid or laminated construction. Alternatively, or additionally, the stator core22may be segmented in form. However, according to certain aspects of the present invention, the stator core22may be fabricated from any one or more of a variety of suitable materials and/or construction methods.

The stator core22preferably includes an annular yoke (not shown) and a plurality of arcuately spaced apart teeth (not shown) extending at least generally radially inward from the yoke. In the exemplary embodiment, the stator core22has six (6) teeth, such that the stator16is a six (6) slot stator. However, it is contemplated that the stator16can have any number of teeth/slots that enables the stator16to function as described herein. While not illustrated inFIG. 1, the plurality of coils (discussed above) are formed by electrically conductive wiring wound being about each of the teeth. The wiring encircles each tooth to form the coils, with each of the coils corresponding to one of the teeth. The wiring is preferably copper, although aluminum or any one or more of a variety of electrically conductive materials may be used without departing from the scope of the present invention.

The electrically insulative coverings24include a plurality of end caps. Additionally, or alternatively, use of any one or more of a variety of insulation means, including but not limited to the use of electrically insulative overmolding, powder-coating, inserts, and/or liners, is contemplated according to certain aspects of the present invention. Furthermore, it is contemplated that in some aspects of the present invention, the stator core22is devoid of electrical insulation. In the illustrated embodiment, the end caps (i.e., coverings24) preferably include a substantially electrically insulative material. In a preferred embodiment, the end caps are fabricated from a synthetic resin. However, in certain aspects of the present invention, it is contemplated that any one or more of a variety of substantially electrically insulative materials may be used to fabricate the electrically insulative coverings24without departing from the scope of the present invention.

The rotor18is illustrated as a brushless permanent magnet rotor assembly. In the exemplary embodiment, the rotor18is includes a rotor core26, a plurality of internally embedded magnets28fitted into magnet-receiving slots (not shown), and a shaft30, which defines a rotational axis for the rotor. The rotational axis of the rotor18is coaxial with the axis of rotation “A.”

The rotor core26is generally cylindrical in form and preferably is fabricated from steel. The rotor core26may be of either solid or laminated construction. Alternatively, or additionally, the rotor core26may be segmented in form. However, according to certain aspects of the present invention, the rotor core26may be fabricated from any one or more of a variety of suitable materials and/or construction methods.

The internally embedded magnets28are each preferably permanent magnets including neodymium or ferrite, although other magnet types and/or compositions are permissible according to certain aspects of the present invention. Furthermore, the internally embedded magnets28are preferably sized and shaped so as to at least in part complement the corresponding magnet-receiving slots.

In the exemplary embodiment, the rotor core26has four (4) internally embedded magnets28, such that the rotor18is a four (4) pole rotor. However, it is contemplated that the rotor18can have any number of internally embedded magnets that enables the rotor18to function as described herein. Accordingly, in the exemplary embodiment, the motor assembly12is of a four (4) pole/six (6) slot construction. However, as described herein, it is contemplated that the motor assembly12can have any number of pole/slot configurations that enable the motor assembly to function as described herein.

As described above, the motor assembly12includes the inner shell20. The inner shell20is generally cylindrical in shape and extends generally circumferentially about the stator16. Alternatively, according to certain aspects of the present invention, the inner shell20may extend about the stator16in such a way as to provide one or more flat sides or to be otherwise alternatively shaped. In the exemplary embodiment, the inner shell20has an outer circumferential surface69and presents axially opposite first and second shell ends32and34, respectively, and extends substantially continuously about the stator16and rotor18to enclose, at least in part, the stator16and rotor18. However, according to certain aspects of the present invention, the inner shell20may include openings or slots therethrough. For example, in certain embodiments, one or more openings or slots may be provided to facilitate ventilation and/or access.

The inner shell20forms a portion of a motor case36of the motor assembly12. The motor case36includes the inner shell20, a flow-directing endshield38, and a blower endshield40(broadly a second endshield). The inner shell20, the flow-directing endshield38, and the blower endshield40, cooperatively define a motor chamber42that at least substantially receives the stator16and the rotor18. More particularly, the flow-directing endshield38is positioned adjacent the first shell end32and coupled thereto. In addition, the blower endshield40is positioned adjacent the second shell end34and coupled thereto. Specifically, the inner shell20is coupled to and held in place between the flow-directing endshield38and the blower endshield40by a plurality of fasteners (not shown) extending between and coupled to the flow-directing endshield38and the blower endshield40. It is contemplated that, in certain aspects of the present invention, the flow-directing endshield38and/or the blower endshield40may be located inwardly or spaced outward from the respective shell ends32and34. That is, each endshield38and40is positioned adjacent or proximate the respective shell ends32and40, in the manner that the endshields38and40are spaced axially apart with the flow-directing endshield38being located closer to first shell end32than the blower endshield40, and the blower endshield40being located closer to the second shell end34than the flow-directing endshield38.

The motor assembly12further includes an outer housing44at least partly surrounding the inner shell20such that an axially extending fluid channel50is defined therebetween. The outer housing44is generally cylindrical in shape and extends generally circumferentially about the inner shell20. Alternatively, according to certain aspects of the present invention, the outer housing44may extend about the inner shell20in such a way as to provide one or more flat sides or to be otherwise alternatively shaped. In the exemplary embodiment, the outer housing44has an inner surface68and presents axially opposite first and second housing ends46and48, respectively, and extends substantially continuously about the inner shell20to enclose, at least in part, the inner shell20, stator16, and rotor18. However, according to certain aspects of the present invention, the outer housing44may include openings or slots therethrough. For example, in certain embodiments, one or more openings or slots may be provided to facilitate ventilation and/or access.

In the exemplary embodiment, as shown inFIG. 2, the first housing end46of the outer housing44extends axially beyond the first shell end32of the inner shell20to define a controller chamber66of the motor assembly12. The second housing end48is coupled to the blower endshield40via a friction fit, although in certain aspects of the present invention, other methods of coupling the second housing end48to the blower endshield40are contemplated. As used herein, the phrase “friction fit” means a value of tightness between two components, i.e., an amount of clearance between the components. A negative amount of clearance is commonly referred to as a press fit, where the magnitude of interference determines whether the fit is a light friction fit or a friction fit. A small amount of positive clearance is referred to as a loose or sliding fit.

The motor assembly12includes first and second bearing assemblies52and54that cooperatively rotatably support the shaft30of the rotor18. The flow-directing endshield38is configured to support the first bearing assembly52, as described further herein, and the blower endshield40is configured to support the second bearing assembly54, as described further herein. Alternative or additional bearing assembly supports may be provided without departing from the scope of the present invention.

Furthermore, in the exemplary embodiment, the motor assembly12includes a motor controller56, positioned, for example, in the controller chamber66. The motor controller56is configured for, at least in part, controlling at least one operational parameter of the motor assembly12, including, for example, providing a means for starting and stopping the motor, selecting forward or reverse rotation, selecting and regulating the speed, regulating or limiting the torque, and protecting against overloads and electrical faults. The motor controller56includes a printed circuit board58(broadly a board) on which a plurality of electronic components are attached. The board58presents opposite first and second radially extending board sides60and62.

In addition, the motor assembly12includes a vent plate64. The vent plate64is configured to close the first housing end46of the outer housing44. In particular, the vent plate64is positioned against the first housing end46and coupled to the flow-directing endshield38via a plurality of fasteners (not shown). Accordingly, as illustrated inFIG. 2, the housing assembly70includes the motor case36(including the inner shell20, the flow-directing endshield38, and the blower endshield40), the outer housing44, and the vent plate64.

In the exemplary embodiment, as described above, the blower endshield40is coupled to the second shell end34and the second housing end48. The flow-directing endshield38is coupled to the first shell end32, holding the inner shell20in place between the flow-directing endshield38and the blower endshield40. Furthermore, the vent plate64is coupled to the flow-directing endshield38such that the outer housing44is held between the blower endshield40and the vent plate64.

FIG. 4is a top perspective view of the flow-directing endshield38,FIG. 5is a bottom perspective view of the flow-directing endshield38,FIG. 6is a top view of the flow-directing endshield38, andFIG. 7is a section view of the flow-directing endshield38, taken about line7-7shown inFIG. 6. In the exemplary embodiment, the flow-directing endshield38is substantially annular in shape. The flow-directing endshield38includes an outermost circular edge72having a diameter D1that is sized to couple to the inner surface68of the outer housing44via a friction fit. While the diameter D1can be any selected diameter, in one preferable embodiment, the diameter D1is about four and sixty-nine hundredths inches (4.69 in.). It is understood that manufacturing tolerances may account for slight variations in the diameter D1of the outermost circular edge72. For example, the manufacturing tolerances may be about ±1.5% of the nominal dimension of the part.

The flow-directing endshield38includes a central aperture74for allowing the shaft30of the rotor18to pass therethrough. For example, in one aspect of the present invention, the shaft30extends through the aperture74and is coupled to an encoder57positioned proximate the controller56.

As shown inFIG. 5, the flow-directing endshield38includes a bearing pocket76for receiving the first bearing assembly52therein to rotatably support at least an end of the shaft30on the flow-directing endshield38. The bearing pocket76is defined by a first axially extending annular wall78extending outward from a bottom surface80of the flow-directing endshield38. The annular wall78is formed substantially concentric with the aperture74.

The flow-directing endshield38also includes a second axially extending annular wall82positioned radially outward from the annular wall78. The annular wall82is formed substantially concentric with the annular wall78and is configured to engage the first shell end32of the inner shell20. In particular, the annular wall82is sized to provide a friction fit with an inner surface of the inner shell20to facilitate coupling the inner shell20to the flow-directing endshield38. It is noted that in certain aspects of the present invention, the inner shell20and the annular wall82may define a slip fit wherein the annular wall82is configured to locate the flow-directing endshield38relative to the inner shell20.

In the exemplary embodiment, the flow-directing endshield38includes an outer periphery84that extends radially between the annular wall82and the outermost circular edge72to at least in part span the fluid channel50(shown inFIG. 2). The outer periphery84includes a flow deflector86that directs a fluid flow radially inward from the fluid channel50. As shown inFIG. 7, the flow deflector86extends at least partially axially upward from a top surface88and at least partially radially inward from the outermost circular edge72, spanning a substantial portion of the outer periphery84. In the exemplary embodiment, in section, the flow deflector86is in the form of a quarter-circle, defining an open arc angle α1of about ninety degrees (90°). Alternatively, the flow deflector can define an open arc having any selected angle α1, open arcs other than circular in form, or can have other sectional forms, including, for example, a single segment, multiple segments, etc.

Referring toFIG. 6, in the exemplary embodiment, the flow deflector86extends arcuately along at least a portion of the outer periphery84at an angle α2of about one hundred and eighty degrees (180°). Alternatively, the flow deflector extends arcuately at any angle α2that enables the flow-directing endshield38to function as described herein. Furthermore, in certain aspects of the present invention, the flow deflector may be segmented, or otherwise include multiple deflectors.

Referring toFIG. 5, the outer periphery84of the flow-directing endshield38includes a plurality of first and second apertures90and92for permitting fluid flow from the fluid channel50past the flow-directing endshield38. Each of the apertures90and92extend arcuately relative to a respective portion of the outermost circular edge72. In the exemplary embodiment, the apertures90and92form a discontinuous ring relative to the outermost circular edge72. The flow deflector86is fluidly aligned with the first apertures90to receive fluid flow from the fluid channel50and turn the fluid flow radially inward.

The flow-directing endshield38includes a plurality of axially extending motor controller mounts94and96, and a plurality of axially extending vent plate mounts98that project axially beyond the motor controller mounts94and96. Each of the motor controller mounts94include an axially extending end portion100configured to engage a hole (not shown) in the printed circuit board58of the motor controller56to facilitate locating the printed circuit board58. In addition, each of the motor controller mounts96include a threaded hole for receiving a fastener (not shown) to secure the printed circuit board58thereto. Furthermore, each of the axially extending vent plate mounts98include a threaded hole102defined therein for receiving a fastener (not shown) to secure the vent plate64thereto.

FIG. 8is a front perspective view of the blower endshield40, andFIG. 9is a rear perspective view of the blower endshield40. In the exemplary embodiment, the blower endshield40is substantially annular in shape including an outermost circular edge110. The blower endshield40includes a central aperture112for allowing the shaft30of the rotor18to pass therethrough, beyond the blower endshield40, for driving connection to the blower14. In the exemplary embodiment, the blower endshield40is configured to couple directly to the blower14.

As shown inFIG. 9, the blower endshield40includes a bearing pocket114for receiving the second bearing assembly54therein to rotatably support at least an end of the shaft30on the blower endshield40. The bearing pocket114is defined by a first axially extending annular wall116extending outward from an inner surface118of the blower endshield40. The annular wall116is formed substantially concentric with the aperture112.

The blower endshield40also includes a second axially extending annular wall120positioned radially outward from the annular wall116. The annular wall120is formed substantially concentric with the annular wall116and has a step122that is configured to engage the second shell end34of the inner shell20. In particular, the step122of the annular wall120is sized to provide a friction fit with an inner surface of the inner shell20to facilitate coupling the inner shell20to the blower endshield40. It is noted that in certain aspects of the present invention, the inner shell20and the step122may define a slip fit wherein the step122is configured to locate the blower endshield40relative to the inner shell20.

In the exemplary embodiment, the blower endshield40includes a plurality of radially extending ribs124extending outward from the annular wall120. The ribs124extend a predefined length L1from the annular wall120. The length L1is selected such that a diametrical distance D2between the outer ends of two diametrically opposite ribs124is sized to couple to the inner surface68of the outer housing44via a friction fit. While the diametrical distance D2can be any selected measure, in one preferable embodiment, the diametrical distance D2is about four and sixty-nine hundredths inches (4.69 in.). It is understood that manufacturing tolerances may account for slight variations in the diametrical distance D2. For example, the manufacturing tolerances may be about ±1.5% of the nominal dimension of the measure.

In the exemplary embodiment, the blower endshield40includes an outer margin126, which is substantially defined by the length L1of the ribs124. That is, the outer margin126extends radially between the annular wall120and the outer ends of the ribs124to at least in part span the fluid channel50(shown inFIG. 2). The outer margin126includes a plurality of fluid-flow openings128for receiving fluid flow from the blower14(e.g., an exhaust air flow). Each of the fluid-flow openings128extend arcuately relative to a respective portion of the annular wall120. In the exemplary embodiment, the fluid-flow openings128form a discontinuous ring relative to the annular wall120. The fluid channel50is fluidly aligned with the fluid-flow openings128to receive fluid flow from the blower14.

Vent Plate

FIG. 10is a perspective view of the vent plate64, in accordance with one aspect of the invention. In the exemplary embodiment, the vent plate64is substantially annular in shape. The vent plate64includes an outermost circular edge130having a diameter D3that is substantially equal to an outer diameter of the outer housing44. The vent plate64includes a plurality of vent openings132to allow fluid flow relative to the outer housing44. In the exemplary embodiment, the vent openings132are defined by elongated louvers, although other shapes are contemplated. For example, the plurality of vent openings132can include one or more apertures, slots, holes, and the like.

In the exemplary embodiment, the vent plate64includes a plurality of fastener openings134. Each fastener opening134is aligned with a respective one of the axially extending vent plate mounts98of the flow-directing endshield38. The vent plate64is configured to couple directly to the axially extending vent plate mounts98, for example, via a fastener (not shown).

Cooling of the Motor Controller

FIG. 3is a sectional view of the motor assembly12, with the stator16and the rotor18removed for clarity. In the exemplary embodiment, the motor assembly12is preferably configured to be operable at temperatures in the range between and including about negative forty (−40) degrees Celsius and about eighty-five (85) degrees Celsius. Such a high operational temperature, in addition to heat generated by the electronic components of the motor controller56and other components of the motor assembly12, make it desirable to cool the motor controller56and associated structures.

As described herein, the outer housing44at least partly surrounds the inner shell20such that the axially extending fluid channel50is defined therebetween. More particularly, in the exemplary embodiment, the inner surface68of the outer housing44is spaced entirely apart from the outer circumferential surface69of the inner shell20to define the fluid channel50. In a preferred embodiment, the inner surface68and the outer circumferential surface69are substantially cylindrical in shape and concentric such that the fluid channel50is annular.

As shown inFIG. 3, the flow-directing endshield38is spaced axially inward from the first housing end46such that the fluid channel50extends axially along only part of the outer housing44. Furthermore, the flow-directing endshield38is fluidly interposed between the fluid channel50and the motor controller56and configured to direct fluid flow between the fluid channel50and the motor controller56.

As described above, the motor controller56includes the board58having opposite first and second radially extending board sides60and62. As shown inFIG. 3, the board includes an outermost peripheral board edge59that is spaced inward from the inner surface68of the outer housing44to enable the fluid flow to pass by the board58.

As described herein, the blower endshield40receives fluid flow directly from the blower14. The fluid flow preferably includes exhaust air from the blower14. However, in certain aspects of the present invention, it is contemplated that the fluid flow is non-exhaust air, an alternative non-air gas (e.g., a refrigerant gas), or even a liquid or mixed fluid (e.g., a vapor) from the blower. Furthermore, in other aspects of the present invention, the fluid flow could be intake air of the blower, in which case the direction of the flow path (introduced below) is reversed. Moreover, in further aspects of the present invention, it is contemplated that the fluid flow is from a non-blower source (e.g., as would be the case for certain non-vacuum motor alternative embodiments).

In the exemplary embodiment, the housing70assembly (shown inFIG. 2) and the motor controller56cooperatively direct fluid flow received from the blower14along a flow path200that extends along the inner shell20and the motor controller56. The fluid flow is operable to remove heat from the inner shell20(e.g., heat generated by the stator16and rotor18) and the motor controller56by means including convection.

In the exemplary embodiment, the first board side60is spaced from the flow-directing endshield38a distance defined by the motor controller mounts94and96. Furthermore, the second board side62is spaced from the vent plate64such that a substantially unobstructed, open space136is provided in controller chamber66between the second board side62and the vent plate64. As such, the motor controller56is provided with dual-sided spacing such that at least a portion of the flow path200extends along each of the first and second board sides60and62of the motor controller56. That is, the flow path200includes an intermediate portion204and a downstream portion206, respectively, extending generally along respective ones of the first and second board sides60and62of the motor controller56.

In the exemplary embodiment, the axially extending fluid channel50defines the upstream portion202of the flow path200. The intermediate portion204of the flow path200is generally cooperatively defined by the top surface88of the flow-directing endshield38and the first board side60. The second board side62and the vent plate64generally cooperatively define the downstream portion206of the flow path200.

Thus, a fluid flow from the blower14is received at the fluid-flow openings128of the blower endshield40and directed generally axially along the upstream portion202of the flow path200by the inner shell20and the outer housing44(e.g., along the fluid channel50defined therebetween). A portion of the fluid flow continues generally axially past the flow-directing endshield38via the second apertures92, while another portion of the fluid flow is channeled in a generally radial direction by the by the flow deflector86to the intermediate portion204of the flow path200. As controlled by the motor controller56and the flow-directing endshield38, the generally radial flowing fluid flow then continues generally along the intermediate portion204. Because the outermost peripheral board edge59is spaced inward from the inner surface68of the outer housing44, the fluid flow along the intermediate portion204is changed from its generally radial direction to flow generally axially past the motor controller56. As controlled by the vent plate64and the second board side62, the fluid flow is channeled generally along the downstream portion206, across the second board side62, before being expelled from the housing assembly70via the plurality of vent openings132.

Advantageously, embodiments of the present invention address cooling a motor controller using air flow generated by a blower powered by the motor assembly. This enables the motor assembly to be manufactured in a smaller size, operated in higher environmental temperatures, and built for a decreased cost. By decreasing the motor assembly size, reductions in weight, power requirements, and cost may be realized. Moreover, enabling operation of the motor assembly in higher temperatures extends the use cases for the motor assembly, facilitating use in conditions previously prohibited.

Although the above description presents features of preferred embodiments of the present invention, other preferred embodiments may also be created in keeping with the principles of the invention. Such other preferred embodiments may, for instance, be provided with features drawn from one or more of the embodiments described above. Yet further, such other preferred embodiments may include features from multiple embodiments described above, particularly where such features are compatible for use together despite having been presented independently as part of separate embodiments in the above description.

Those of ordinary skill in the art will appreciate that any suitable combination of the previously described embodiments may be made without departing from the spirit of the present invention.

The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and access the reasonably fair scope of the present invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention set forth in the following claims.