Motor assembly for a washing machine appliance

A washing machine appliance includes a wash basket rotatably mounted within a wash tub for receiving of a load of articles for washing and a drive motor having a motor shaft for selectively rotating the wash basket and an agitation element. A cooling fan is mechanically coupled to the motor shaft for urging a flow of air as the drive motor rotates the motor shaft and a fan cover is positioned over the cooling fan. The fan cover includes an endcap positioned opposite the cooling fan relative to the drive motor along an axial direction, a peripheral portion defining a plurality of ventilation openings spaced apart along a circumferential direction, and a plurality of louvers positioned over the plurality of ventilation openings for directing the flow of air away from the drive motor.

FIELD OF THE INVENTION

The present subject matter relates generally to washing machine appliances, and more particularly to motor assemblies for washing machine appliances.

BACKGROUND OF THE INVENTION

Washing machine appliances generally include a wash tub for containing water or wash fluid, e.g., water and detergent, bleach, and/or other wash additives. A wash basket is rotatably mounted within the wash tub and defines a wash chamber for receipt of articles for washing, and an agitation element is rotatably mounted within the wash basket. Washing machine appliances are typically equipped to operate in one or more modes or cycles, such as wash, rinse, and spin cycles. For example, during a wash or rinse cycle, the wash fluid is directed into the wash tub in order to wash and/or rinse articles within the wash chamber. In addition, the wash basket and/or the agitation element can rotate at various speeds to agitate or impart motion to articles within the wash chamber, to wring wash fluid from the articles, etc.

To facilitate rotation of the wash basket during the various operating cycles, conventional washing machine appliances include a motor assembly that is mechanically coupled to the wash basket. Notably, the performance of conventional operating cycles may be limited due to temperature restrictions related to drive motor or other components of the motor assembly. In this regard, conventional motor assemblies typically generate significant heat during operation, necessitating the implementation of cool-down periods, performance of cycles at reduced speeds, or other heat mitigation steps or procedures.

Accordingly, a washing machine appliance including features for improved and prolonged operation of a motor assembly would be useful. More specifically, a motor assembly for a washing machine appliance that includes integral features for facilitating the cooling of the motor, e.g., to maximize the operating envelope of the motor without requiring costly heat mitigation techniques, would be particularly beneficial.

BRIEF DESCRIPTION OF THE INVENTION

In one exemplary embodiment, a washing machine appliance is provided including a wash tub positioned within a cabinet and defining a wash chamber, a wash basket rotatably mounted within the wash tub for receiving of a load of articles for washing, an agitation element rotatably mounted within the wash basket, a drive motor having a motor shaft defining an axial direction and being operably coupled to the wash basket and the agitation element for selectively rotating the wash basket and the agitation element, a cooling fan mechanically coupled to the motor shaft for urging a flow of air as the drive motor rotates the motor shaft, and a fan cover positioned over the cooling fan. The fan cover includes an endcap positioned opposite the cooling fan relative to the drive motor along the axial direction, a peripheral portion defining a plurality of ventilation openings spaced apart along a circumferential direction, and a plurality of louvers positioned over the plurality of ventilation openings for directing the flow of air away from the drive motor.

In another exemplary embodiment, a fan cover for a washing machine appliance is provided. The washing machine appliance includes a wash basket rotatably mounted within a wash tub, an agitation element rotatably mounted within the wash basket, a drive motor having a motor shaft defining an axial direction and being operably coupled to the wash basket and the agitation element for selectively rotating the wash basket and the agitation element, and a cooling fan mechanically coupled to the motor shaft for urging a flow of air as the drive motor rotates the motor shaft. The fan cover includes an endcap positioned opposite the cooling fan relative to the drive motor along the axial direction, a peripheral portion defining a plurality of ventilation openings spaced apart along a circumferential direction, and a plurality of louvers positioned over the plurality of ventilation openings for directing the flow of air away from the drive motor.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “upstream” and “downstream” refer to the relative flow direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the flow direction from which the fluid flows, and “downstream” refers to the flow direction to which the fluid flows. The terms “includes” and “including” are intended to be inclusive in a manner similar to the term “comprising.” Similarly, the term “or” is generally intended to be inclusive (i.e., “A or B” is intended to mean “A or B or both”).

FIGS. 1 through 3illustrate an exemplary embodiment of a vertical axis washing machine appliance100. Specifically,FIGS. 1 and 2illustrate perspective views of washing machine appliance100in a closed and an open position, respectively.FIG. 3provides a side cross-sectional view of washing machine appliance100. Washing machine appliance100generally defines a vertical direction V, a lateral direction L, and a transverse direction T, each of which is mutually perpendicular, such that an orthogonal coordinate system is generally defined.

While described in the context of a specific embodiment of vertical axis washing machine appliance100, it should be appreciated that vertical axis washing machine appliance100is provided by way of example only. It will be understood that aspects of the present subject matter may be used in any other suitable washing machine appliance, such as a horizontal axis washing machine appliance. Indeed, modifications and variations may be made to washing machine appliance100, including different configurations, different appearances, and/or different features while remaining within the scope of the present subject matter.

Washing machine appliance100has a cabinet102that extends between a top portion104and a bottom portion106along the vertical direction V, between a first side (left) and a second side (right) along the lateral direction L, and between a front and a rear along the transverse direction T. As best shown inFIG. 3, a wash tub108is positioned within cabinet102, defines a wash chamber110, and is generally configured for retaining wash fluids during an operating cycle. Washing machine appliance100further includes a primary dispenser112(FIG. 2) for dispensing wash fluid into wash tub108. The term “wash fluid” refers to a liquid used for washing and/or rinsing articles during an operating cycle and may include any combination of water, detergent, fabric softener, bleach, and other wash additives or treatments.

In addition, washing machine appliance100includes a wash basket114that is positioned within wash tub108and generally defines an opening116for receipt of articles for washing. More specifically, wash basket114is rotatably mounted within wash tub108such that it is rotatable about an axis of rotation A. According to the illustrated embodiment, the axis of rotation A is substantially parallel to the vertical direction V. In this regard, washing machine appliance100is generally referred to as a “vertical axis” or “top load” washing machine appliance100. However, it should be appreciated that aspects of the present subject matter may be used within the context of a horizontal axis or front load washing machine appliance as well.

As illustrated, cabinet102of washing machine appliance100has a top panel118. Top panel118defines an opening (FIG. 2) that coincides with opening116of wash basket114to permit a user access to wash basket114. Washing machine appliance100further includes a door120which is rotatably mounted to top panel118to permit selective access to opening116. In particular, door120selectively rotates between the closed position (as shown inFIGS. 1 and 3) and the open position (as shown inFIG. 2). In the closed position, door120inhibits access to wash basket114. Conversely, in the open position, a user can access wash basket114. A window122in door120permits viewing of wash basket114when door120is in the closed position, e.g., during operation of washing machine appliance100. Door120also includes a handle124that, e.g., a user may pull and/or lift when opening and closing door120. Further, although door120is illustrated as mounted to top panel118, door120may alternatively be mounted to cabinet102or any other suitable support.

As best shown inFIGS. 2 and 3, wash basket114further defines a plurality of perforations126to facilitate fluid communication between an interior of wash basket114and wash tub108. In this regard, wash basket114is spaced apart from wash tub108to define a space for wash fluid to escape wash chamber110. During a spin cycle, wash fluid within articles of clothing and within wash chamber110is urged through perforations126wherein it may collect in a sump128defined by wash tub108. Washing machine appliance100further includes a pump assembly130(FIG. 3) that is located beneath wash tub108and wash basket114for gravity assisted flow when draining wash tub108.

An impeller or agitation element132(FIG. 3), such as a vane agitator, impeller, auger, oscillatory basket mechanism, or some combination thereof is disposed in wash basket114to impart an oscillatory motion to articles and liquid in wash basket114. More specifically, agitation element132extends into wash basket114and assists agitation of articles disposed within wash basket114during operation of washing machine appliance100, e.g., to facilitate improved cleaning. In different embodiments, agitation element132includes a single action element (i.e., oscillatory only), a double action element (oscillatory movement at one end, single direction rotation at the other end) or a triple action element (oscillatory movement plus single direction rotation at one end, single direction rotation at the other end). As illustrated inFIG. 3, agitation element132and wash basket114are oriented to rotate about axis of rotation A (which is substantially parallel to vertical direction V).

As best illustrated inFIG. 3, washing machine appliance100includes a motor assembly200(described in detail below) in mechanical communication with wash basket114to selectively rotate wash basket114(e.g., during an agitation or a rinse cycle of washing machine appliance100). In addition, motor assembly200may also be in mechanical communication with agitation element132. In this manner, motor assembly200may be configured for selectively rotating or oscillating wash basket114and/or agitation element132during various operating cycles of washing machine appliance100.

Referring still toFIGS. 1 through 3, a control panel150with at least one input selector152(FIG. 1) extends from top panel118. Control panel150and input selector152collectively form a user interface input for operator selection of machine cycles and features. A display154of control panel150indicates selected features, operation mode, a countdown timer, and/or other items of interest to appliance users regarding operation.

Operation of washing machine appliance100is controlled by a controller or processing device156that is operatively coupled to control panel150for user manipulation to select washing machine cycles and features. In response to user manipulation of control panel150, controller156operates the various components of washing machine appliance100to execute selected machine cycles and features. According to an exemplary embodiment, controller156may include a memory and microprocessor, such as a general or special purpose microprocessor operable to execute programming instructions or micro-control code associated with methods described herein. Alternatively, controller156may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software. Control panel150and other components of washing machine appliance100may be in communication with controller156via one or more signal lines or shared communication busses.

During operation of washing machine appliance100, laundry items are loaded into wash basket114through opening116, and washing operation is initiated through operator manipulation of input selectors152. Wash basket114is filled with water and detergent and/or other fluid additives via primary dispenser112. One or more valves can be controlled by washing machine appliance100to provide for filling wash tub108and wash basket114to the appropriate level for the amount of articles being washed and/or rinsed. By way of example for a wash mode, once wash basket114is properly filled with fluid, the contents of wash basket114can be agitated (e.g., with agitation element132as discussed previously) for washing of laundry items in wash basket114.

More specifically, referring again toFIG. 3, a water fill process will be described according to an exemplary embodiment. As illustrated, washing machine appliance100includes a water supply conduit160that provides fluid communication between a water supply source162(such as a municipal water supply) and a discharge nozzle164for directing a flow of water into wash chamber110. In addition, washing machine appliance100includes a water fill valve or water control valve166which is operably coupled to water supply conduit160and communicatively coupled to controller156. In this manner, controller156may regulate the operation of water control valve166to regulate the amount of water within wash tub108. In addition, washing machine appliance100may include one or more pressure sensors170for detecting the amount of water and or clothes within wash tub108. For example, pressure sensor170may be operably coupled to a side of tub108for detecting the weight of wash tub108, which controller156may use to determine a volume of water in wash chamber110and a subwasher load weight.

After wash tub108is filled and the agitation phase of the wash cycle is completed, wash basket114can be drained, e.g., by drain pump assembly130. Laundry articles can then be rinsed by again adding fluid to wash basket114depending on the specifics of the cleaning cycle selected by a user. The impeller or agitation element132may again provide agitation within wash basket114. One or more spin cycles may also be used as part of the cleaning process. In particular, a spin cycle may be applied after the wash cycle and/or after the rinse cycle in order to wring wash fluid from the articles being washed. During a spin cycle, wash basket114is rotated at relatively high speeds to help wring fluid from the laundry articles through perforations126. After articles disposed in wash basket114are cleaned and/or washed, the user can remove the articles from wash basket114, e.g., by reaching into wash basket114through opening116.

Referring now toFIGS. 3 and 4, a motor assembly200will be described according to an exemplary embodiment of the present subject matter. Motor assembly200may be used with washing machine appliance100, e.g., to facilitate rotation of wash basket114and/or agitation element132, as described above. In addition, motor assembly200may be used in other washing machine appliances, including both vertical and horizontal axis washing machine appliances. As described in detail below, motor assembly200includes features for rotating wash basket114while also generating a flow of cooling air (e.g., identified schematically inFIGS. 6 and 7by reference numeral202) to help reduce the operating temperature of motor assembly200, thereby expanding its overall operating envelope and performance capabilities. It should be appreciated that motor assembly200described herein is only an exemplary embodiment used to describe aspects of the present subject matter and is not intended to limit the scope of the present disclosure in any manner.

As shown, motor assembly200generally includes a drive motor204that is operably coupled to wash basket114for selectively rotating wash basket114. More specifically, for example, drive motor204may include a motor shaft206that defines an axial direction A, a radial direction R, and a circumferential direction C. According to the exemplary embodiment, drive motor204is a vertically oriented, e.g., such that motor shaft206extends parallel to the vertical direction V of washing machine appliance100(i.e., such that axial direction A is parallel to the vertical direction V). However, it should be appreciated that aspects of the present subject matter may apply to any other suitable motor arrangement, e.g., such as a horizontally mounted motor assembly for a front load washing machine appliance.

As used herein, “motor” may refer to any suitable drive motor and/or transmission assembly for rotating wash basket114. For example, drive motor204may be a brushless DC electric motor, a stepper motor, or any other suitable type or configuration of motor. For example, drive motor204may be an AC motor, an induction motor, a permanent magnet synchronous motor, or any other suitable type of AC motor. In addition, drive motor204may include any suitable transmission assemblies, clutch mechanisms, or other components. According to an exemplary embodiment, drive motor204may be operably coupled to controller156, which is programmed to rotate wash basket114according to predetermined operating cycles, based on user inputs (e.g. via control panel150or input selectors152), etc.

Motor assembly200may further include a transmission assembly210that is operably coupled to wash basket114and/or agitation element132for transmitting torque from motor shaft206. In general, transmission assembly210may be any suitable mechanism or device suitable for utilizing the rotational motion of motor shaft206to rotate wash basket114and/or agitation element132. Accordingly, aspects of the present subject matter are not limited to the specific transmission assembly210described herein according to an exemplary embodiment.

Specifically, as best shown inFIG. 4, transmission assembly210is a belt driven transmission. In this regard, transmission assembly210includes a drive pulley212that is directly mechanically coupled to motor shaft206. Drive pulley212is generally configured for transmitting torque to an input shaft214of transmission assembly210via a drive belt216. As shown, input shaft214and motor shaft206are both vertically oriented in parallel to each other. In addition, motor shaft206and drive pulley212both extend out of a bottom surface218of drive motor204and input shaft214extends from a bottom of wash basket114to a location proximate bottom106of cabinet102. However, it should be appreciated that according to alternative embodiments, any other suitable motor and transmission configuration may be used.

Referring still toFIG. 4, input shaft214may be mechanically coupled to an output shaft220that is coupled to wash basket114and/or agitation element132. More specifically, as shown, input shaft214and output shaft220are rotatably supported by one or more bearings222and are mechanically coupled through a gearbox224, a mode shifter226, and a clutch228. In general, gearbox224includes a plurality of gears encased in a housing for altering the torque and/or speed transmitted from input shaft214to output shaft220. In addition, mode shifter226may be any suitable mechanism, gear train, etc. that is generally configured for adjusting the rotating action of output shaft220, e.g., to facilitate various agitation profiles or programs depending on the operating cycle of washing machine appliance100. Clutch228may be any suitable device for selectively engaging or disengaging input shaft214and output shaft220, e.g., for engaging and disengaging wash basket114and/or agitation element132.

Notably, motor assembly200and transmission assembly210may operate together to facilitate multiple modes of operation of washing machine appliance100. For example, during a wash cycle or an agitation cycle, wash basket114may remain stationary and agitation element132may oscillate back and forth according to any suitable agitation profile. This may be achieved, for example, by disengaging mode shifter226and/or clutch228to mechanically decouple wash basket114from drive belt216while operating drive motor204in a bi-directional, oscillating manner. By contrast, during a drain cycle or a spin cycle, wash basket114and agitation element132may rotate in the same direction at high speeds. This may be achieved, for example, by engaging mode shifter226and/or clutch228to mechanically couple wash basket114to drive belt216while operating drive motor204in a single direction. It should be appreciated that other modes of operating, along with other means for transmitting torque from motor assembly200may be used while remaining within the scope of the present subject matter.

Notably, operation of drive motor204generates heat within cabinet102. If this heat exceeds certain thresholds and is not discharged away from drive motor204, the operating limits of drive motor204may result in restrictions on the performance capabilities and operating envelope of motor assembly200. As a result, aspects of the present subject matter are directed to systems and features for facilitating cooling of motor assembly200, e.g., thereby facilitating improved performance of motor assembly200and washing machine appliance100.

Specifically, according to exemplary embodiments of the present subject matter, washing machine appliance100may include a fan assembly240that is generally configured for cooling drive motor204during operation of washing machine appliance100. More specifically, referring still toFIG. 4, fan assembly240may generally include a cooling fan242that is mechanically coupled to motor shaft206for urging a flow of cooling air around drive motor204as it rotates motor shaft206. In addition, fan assembly240may include a fan housing or a fan cover244that is positioned over cooling fan242and is generally configured for preventing access to moving parts of drive motor204and/or fan assembly240. Each of these features of fan assembly240will be described in more detail below according to exemplary embodiments of the present subject matter.

In general, cooling fan242may generally be any suitable type and configuration of fan or other air moving device. For example, cooling fan242is illustrated as a centrifugal fan directly coupled to motor shaft206such that it rotates about the axial direction A. However, according to alternative embodiments, cooling fans242may be a tangential fan, an axial fan, or any other suitable air blower. Notably, regardless of the type and configuration of fan used, the space available within cabinet102for positioning and rotating cooling fan242is very limited. Therefore, aspects of the present subject matter are directed to unique designs of fan assembly240to facilitate improved cooling of the motor assembly200during operation.

Referring now also toFIGS. 5 through 7, fan cover244will be described in more detail according to an exemplary embodiment of the present subject matter. As shown, fan cover244generally includes an endcap250that is positioned opposite cooling fan242relative to drive motor204along the axial direction A. In other words, endcap250is generally a flat portion of fan cover244and cooling fan242is sandwiched between drive motor204and endcap250. Fan cover244further includes a peripheral portion252that extends from endcap250and wraps around a radial tip of cooling fan242, e.g., to prevent user access to moving parts of drive motor204or cooling fan242during operation.

According to the illustrated embodiment, fan cover244is designed not only to cover cooling fan242, but also to cover other portions of transmission assembly210. In this regard, for example, fan cover244may further define a belt cover254that extends from fan cover244is positioned over drive belt216, mode shifter226, clutch228, etc. Notably, to facilitate the discharge of air flow202generated by cooling fan242, fan cover244and belt cover254may define a plurality of apertures. Specifically, according to the illustrated embodiment, fan cover244may define a plurality of ventilation apertures256and belt cover254may define a plurality of belt cover apertures258for passing the flow of cooling air. In general, fan cover244and belt cover254may define any suitable number, type, geometry, size, and configuration of apertures256,258for facilitating improved airflow from fan assembly240.

For example, according to the illustrated embodiment, a plurality of smaller ventilation apertures256may be spaced in a circular pattern on endcap250, e.g., surrounding motor shaft206. Moreover, according to an exemplary embodiment, the overall size of ventilation apertures256may increase progressively from a central axis of motor shaft206or the axial direction A toward peripheral portion252. According to the illustrated embodiment, peripheral portion252defines a plurality of ventilation apertures256that are spaced apart along the circumferential direction C.

Moreover, according to the illustrated embodiment, fan cover244may further include a plurality of louvers260that are positioned over the plurality of ventilation apertures256for directing the flow of air202away from drive motor204. Specifically, according to the illustrated embodiment, louvers260are positioned over ventilation apertures256defined on peripheral portion252. As will be described in more detail below, the size, angular orientation, geometry, and angle magnitude may vary from louver to louver260to facilitate improved discharge of heated air202and improved performance of fan assembly240.

According to the exemplary embodiment described herein, louvers260are bidirectional such that a portion of louvers260positioned on one end of peripheral portion252are oriented in one direction (e.g., in a clockwise orientation) while louvers260positioned on the other end of peripheral portion252are oriented in the other direction (e.g., in a counterclockwise orientation). Notably, this configuration may provide improved discharge of heated air as drive motor204cycles through the various modes of operation, some of which rotate clockwise and some of which rotate counterclockwise.

As best illustrated inFIGS. 6 and 7, each louver260may define an extension angle262that is measured relative to a tangent line264defined by fan cover244at a center of peripheral portion252(e.g., a center along the axial direction A) at the location of each respective louver260. Notably, according to exemplary embodiments of the present subject matter, the extension angle262of louvers260may vary about the circumferential direction C in order to improve the operation of fan assembly240. Thus, at least two of the louvers260define a different extension angle262. According to still other embodiments, every louver260defines a different extension angle262.

According to the illustrated embodiment, louvers260are only positioned over ventilation apertures256defined in peripheral portion252. In addition, peripheral portion244merges into belt cover254such that peripheral portion252extends through an arc length266measured along the circumferential direction C before merging with belt cover254. According to exemplary embodiments, arc length266is between about 195 and 315 degrees, between about 215 and 295 degrees, between about 235 and 275 degrees, about 255 degrees, or any other suitable arc length. However, it should be appreciated that according to alternative embodiments, peripheral portion252may define any suitable arc length266and louvers260may be defined over any other suitable ventilation apertures256and/or belt cover apertures258.

According to exemplary embodiments of the present subject matter, the size, angle, and/or orientation of louvers260may vary at least in part based on their location on fan cover244. In this manner, as described briefly above, the position of ventilation apertures256and the selective orientation of the louvers260with respect to the circumferential discharge region of fan assembly240directs the heated air202around drive motor204away from drive motor204resulting improved cooling during both the agitation and spin portions of the operating cycle. In this regard, for example, louvers260oriented in one direction might be more efficient at cooling drive motor204while rotating one direction (e.g., clockwise, as shown inFIG. 6) during an agitation cycle, while louvers260oriented in another direction might be more efficient at cooling drive motor204while rotating the opposite direction (e.g., counterclockwise as shown inFIG. 7) during a spin cycle. Exemplary positioning of ventilation apertures260and geometries of louvers260are provided below according to an exemplary embodiment. However, it should be appreciated the modifications may be made to these features while remaining within the scope of the present subject matter.

According to the illustrated embodiment, a transition line270is defined by fan cover244which divides fan cover244into a first portion272and a second portion274. More specifically, as illustrated, transition line270divides fan cover244in half, such that first portion272is a mirror image of second portion274. In addition, when viewed in plane defined perpendicular to the axial direction A, transition line270extends through motor shaft206and input shaft214and terminates at a transition point276at a distal end of transition line270, i.e., at a point farthest away from input shaft214. As such, transition line270also extends directly through a center of drive belt216.

As shown, transition point276may be the point at which the directional orientation louvers260changes. In this regard, louvers260may be substantially flat or have an extension angle262of approximately 0 degrees at the transition point and their extension angle262may increase progressively from transition point276moving around along the circumferential direction C until peripheral portion242merges with belt cover254. For example, louvers260may increase progressively from the transition point276to a maximum extension angle262. According to exemplary embodiments, the maximum extension angle262may be between about 0 and 45 degrees, between about 5 and 35 degrees, between about 10 and 25 degrees, between about 15 and 20 degrees, or any other suitable angle. According to still other embodiments, the maximum extension angle262may be different between first portion272and second portion274. In this regard, for example, the maximum extension angle262may vary depending on the operating characteristics or speeds of drive motor204in the agitation, spin, or other operating cycles.

In addition, it should be appreciated that the geometry of louvers260may vary, e.g., along the axial direction A. In this regard, louvers260may generally be curved to wrap around peripheral portion252from drive motor204toward endcap250. The angle of curvature may be similar to the angle of curvature of peripheral portion252. According to still other embodiments, louvers260may be straight fins, may be one or more aligned baffles, or may have any other suitable size, geometry, and/or configuration.

The motor assembly described above facilitates reduced temperature operation of the motor assembly throughout various operating cycles of a washing machine appliance. In this regard, the integral fan directs air flow away from the motor, thereby discharging heated air and cooling components proximate motor assembly. This in turn reduces or eliminates restrictions on the operating envelope of the motor assembly for improved power, performance, and efficiency. Moreover, reduced temperature operation results in prolonged life of the motor, fewer maintenance visits and replacement parts, etc.