Patent Application
20200232140
The present subject matter relates generally to washing machine appliances, such as horizontal axis washing machine appliances, and methods for monitoring load balances in such washing machine appliances.
Washing machine appliances generally include a cabinet which receives a wash tub for containing water or wash fluid (e.g., water and detergent, bleach, or other wash additives). The wash tub may be suspended within the cabinet by a suspension system to allow some movement relative to the cabinet during operation. A basket is rotatably mounted within the wash tub and defines a wash chamber for receipt of articles for washing. During normal operation of such washing machine appliances, the wash fluid is directed into the wash tub and onto articles within the wash chamber of the basket. A drive assembly is coupled to the wash tub and configured to rotate the wash basket within the wash tub to agitate articles within the wash chamber, to wring wash fluid from articles within the wash chamber, etc.
A significant concern during operation of washing machine appliances is the balance of the tub. For example, articles and water loaded within a basket may not be equally weighted about a central axis of the basket and tub. Accordingly, when the basket rotates, in particular during a spin cycle, the imbalance in clothing weight may cause the basket to be out-of-balance within the tub, such that the axis of rotation does not align with the cylindrical axis of the basket or tub. Such out-of-balance issues can cause the basket to contact the tub during rotation and can further cause movement of the tub within the cabinet. Significant movement of the tub can, in turn, generate increased noise and vibrations and/or cause excessive wear and premature failure of appliance components.
Various methods are known for monitoring load balances and preventing out-of-balance scenarios within washing machine appliances. Such monitoring and prevention may be especially important, for instance, during the high-speed rotation of the wash basket, e.g., during a spin cycle. For example, conventional systems monitor motor current or rotational velocity to determine when articles within the tub are in a suitable position for a spin cycle. Alternatively, one or more balancing rings may be attached to the rotating basket to provide a rotating annular mass that minimizes the effects of imbalances. However, such systems often fail to accurately determine the position of articles within the tub or basket or detect or compensate for an out-of-balance condition. Moreover, such systems often require additional components and/or sensors, thereby increasing the cost and complexity of the appliance.
Accordingly, improved methods and apparatuses for monitoring load balance in washing machine appliances are desired. In particular, methods and apparatuses that provide for compensation for an imbalanced state during a washing operation would be advantageous.
Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In one exemplary aspect of the present disclosure, a method for operating a washing machine appliance is provided. The washing machine appliance has a wash tub, a wash basket rotatably mounted within the wash tub, and a balancing system comprising a plurality of fluid chambers defined in the wash basket. The method includes rotating the wash basket within the wash tub at a basket speed. The method also includes receiving, with the balancing system, a first signal from a measurement device and receiving, with the balancing system, a second signal from a controller of the washing machine appliance. The method further includes opening a valve to provide fluid to at least one of the plurality of fluid chambers of the balancing system based on the first signal and the second signal.
In another exemplary aspect of the present disclosure, a washing machine appliance is provided including a cabinet and a wash tub positioned within the cabinet. The washing machine appliance also includes a measurement device configured for sending a first signal to a balancing system of the washing machine appliance. The washing machine appliance further includes a controller. The controller is configured for rotating the wash basket within the wash tub at a basket speed and sending a second signal to the balancing system of the washing machine appliance. The balancing system is configured for opening a valve to provide fluid to at least one of a plurality of fluid chambers of the balancing system based on the first signal and the second signal.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.
Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.
Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
In order to aid understanding of this disclosure, several terms are defined below. The defined terms are understood to have meanings commonly recognized by persons of ordinary skill in the arts relevant to the present invention. 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”). The terms “first,” “second,” and “third” may be used interchangeably to distinguish one element from another and are not intended to signify location or importance of the individual elements. Furthermore, it should be appreciated that as used herein, terms of approximation, such as “approximately,” “substantially,” or “about,” refer to being within a ten percent margin of error.
Referring now to the figures,
Referring to
Wash basket 122 may define one or more agitator features that extend into wash chamber 124 to assist in agitation and cleaning articles disposed within wash chamber 124 during operation of washing machine appliance 100. For example, as illustrated in
Washing machine appliance 100 includes a drive assembly 128 which is coupled to wash tub 120 and is generally configured for rotating wash basket 122 during operation, e.g., such as during an agitation or spin cycle. More specifically, as best illustrated in
Referring generally to
In some embodiments, a window 146 in door 144 permits viewing of wash basket 122 when door 144 is in the closed position (e.g., during operation of washing machine appliance 100). Door 144 also includes a handle (not shown) that, for example, a user may pull when opening and closing door 144. Further, although door 144 is illustrated as mounted to front panel 140, it should be appreciated that door 144 may be mounted to another side of cabinet 102 or any other suitable support according to alternative embodiments. Additionally or alternatively, a front gasket or baffle (not shown) may extend between tub 120 and the front panel 140 about the opening 142 covered by door 144, further sealing tub 120 from cabinet 102.
Referring again to
Turning briefly to
Additionally or alternatively, washing machine appliance 100 can include other vibration damping elements, such as one or more suspension springs 164. According to the illustrated embodiment, suspension system 160 includes two suspension springs 164 that extend between top 104 of cabinet 102 and sides of wash tub 120, e.g., to be fixed at a location proximate to but above a center of gravity of wash tub 120. In optional embodiments, suspension system 160 (and washing machine appliance 100, generally) is free of any annular balancing rings, which would add an evenly-distributed rotating mass on basket 122.
Still referring to
Returning to
As illustrated, a detergent drawer 172 may be slidably mounted within front panel 140. Detergent drawer 172 receives a wash additive (e.g., detergent, fabric softener, bleach, or any other suitable liquid or powder) and directs the fluid additive to wash chamber 124 during operation of washing machine appliance 100. According to the illustrated embodiment, detergent drawer 172 may also be fluidly coupled to spout 170 to facilitate the complete and accurate dispensing of wash additive.
In optional embodiments, a bulk reservoir 174 is disposed within cabinet 102. Bulk reservoir 174 may be configured for receipt of fluid additive for use during operation of washing machine appliance 100. Moreover, bulk reservoir 174 may be sized such that a volume of fluid additive sufficient for a plurality or multitude of wash cycles of washing machine appliance 100 (e.g., five, ten, twenty, fifty, or any other suitable number of wash cycles) may fill bulk reservoir 174. Thus, for example, a user can fill bulk reservoir 174 with fluid additive and operate washing machine appliance 100 for a plurality of wash cycles without refilling bulk reservoir 174 with fluid additive. A reservoir pump 176 is configured for selective delivery of the fluid additive from bulk reservoir 174 to wash tub 120.
A control panel 180 including a plurality of input selectors 182 is coupled to front panel 140. Control panel 180 and input selectors 182 collectively form a user interface input for operator selection of machine cycles and features. A display 184 of control panel 180 indicates selected features, operation mode, a countdown timer, and/or other items of interest to appliance users regarding operation.
Operation of washing machine appliance 100 is controlled by a processing device or a controller 186 that is operatively coupled to control panel 180 for user manipulation to select washing machine cycles and features. In response to user manipulation of control panel 180, controller 186 operates the various components of washing machine appliance 100 to execute selected machine cycles and features. Controller 186 may 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. The memory may represent random access memory such as DRAM, or read only memory such as ROM or FLASH. In one embodiment, the processor executes programming instructions stored in memory. The memory may be a separate component from the processor or may be included onboard within the processor. Alternatively, controller 186 may 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 panel 180 and other components, such as measurement devices 190 and a balancing system 200 (described in more detail below) of washing machine appliance 100 may be in communication with controller 186 via one or more signal lines or shared communication busses to provide signals to and/or receive signals from the controller 186. Similar to the controller 186, the measurement devices 190 may include a microprocessor that performs the calculations specific to the measurement of motion with the calculation results being used by or communicated to the controller 186 and/or balancing system 200, as will be described in more detail below. According to exemplary embodiments, the at least one measurement device 190 may include a dedicated microprocessor that performs the calculations specific to the measurement of motion, such that the measurement device(s) 190 is/are operationally independent of the controller 186.
As illustrated for example in
A measurement device 190 in accordance with the present disclosure may include an accelerometer which measures translational motion, such as acceleration along one or more directions. Additionally or alternatively, a measurement device 190 may include a gyroscope, which measures rotational motion, such as rotational velocity about an axis. Moreover, according to exemplary embodiments, a measurement device 190 may include more than one gyroscope and/or more than one accelerometer.
As will be described in greater detail below, movement may be measured as one or more displacement readings, e.g., certain displacement amplitudes A1, A2, and A3 (see
In exemplary embodiments, a measurement device 190 may include at least one gyroscope and/or at least one accelerometer. The measurement device 190, for example, may be a printed circuit board which includes the gyroscope and accelerometer thereon. The measurement device 190 may be mounted to the tub 120 (e.g., via a suitable mechanical fastener, adhesive, etc.) and may be oriented such that the various sub-components (e.g., the gyroscope and accelerometer) are oriented to measure movement along or about particular directions as discussed herein. Notably, the gyroscope and accelerometer in exemplary embodiments may be advantageously mounted at a single location on the tub 120 (e.g., the location of the printed circuit board or other component of the measurement device 190 on which the gyroscope and accelerometer are grouped). Such positioning at a single location advantageously reduces the costs and complexity (e.g., due to additional wiring, etc.) of out-of-balance detection, while still providing relatively accurate out-of-balance detection as discussed herein. Alternatively, however, the gyroscope and accelerometer need not be mounted on the tub 120 at a single location. For example, a gyroscope located at one location can measure the rotation of an accelerometer located at a different location, because rotation about a given axis is the same everywhere on a solid object such as tub 120.
In exemplary embodiments, during operation of washing machine appliance 100, laundry items are loaded into wash basket 122 through opening 142, and a wash operation is initiated through operator manipulation of input selectors 182. For example, a wash cycle may be initiated such that wash tub 120 is filled with water, detergent, or other fluid additives (e.g., via detergent drawer 172 or bulk reservoir 174). One or more valves (not shown) can be controlled by washing machine appliance 100 to provide for filling wash basket 122 to the appropriate level for the amount of articles being washed or rinsed. By way of example, once wash basket 122 is properly filled with fluid, the contents of wash basket 122 can be agitated (e.g., with ribs 126) for an agitation phase of laundry items in wash basket 122. During the agitation phase, the basket 122 may be motivated about the axis of rotation A at a set speed (e.g., first speed or tumble speed). As the basket 122 is rotated, articles within the basket 122 may be lifted and permitted to drop therein.
After the agitation phase of the washing operation is completed, wash tub 120 can be drained, e.g., by drain pump assembly 156. Laundry articles can then be rinsed (e.g., through a rinse cycle) by again adding fluid to wash tub 120, depending on the particulars of the cleaning cycle selected by a user. Ribs 126 may again provide agitation within wash basket 122. One or more spin cycles may also be used. In particular, a spin cycle may be applied after the wash cycle or after the rinse cycle in order to wring wash fluid from the articles being washed. During a spin cycle, basket 122 is rotated at relatively high speeds. For instance, basket 122 may be rotated at one set speed (e.g., second speed or pre-plaster speed) before being rotated at another set speed (e.g., third speed or plaster speed). As would be understood, the pre-plaster speed may be greater than the tumble speed and the plaster speed may be greater than the pre-plaster speed. Moreover, agitation or tumbling of articles may be reduced as basket 122 increases its rotational velocity such that the plaster speed maintains the articles at a generally fixed position relative to basket 122. After articles disposed in wash basket 122 are cleaned (or the washing operation otherwise ends), a user can remove the articles from wash basket 122 (e.g., by opening door 144 and reaching into wash basket 122 through opening 142).
Referring now specifically to
As shown in
For purposes of the present illustration, the suspended mass of washing machine appliance 100 is separated into parts convenient for the purpose of showing how the forces at the shaft bearings 134, 136 have the same magnitude at equilibrium whether they are acting on the rotating mass (i.e., wash basket 122) from one side of the bearings or on the non-rotating mass (i.e., wash tub 120) from the other side. The spinning out-of-balance mass has a centrifugal force (FOOB) that causes the acceleration of all other suspended masses, e.g., wash tub 120 and wash basket 122, to reach equilibrium with the out-of-balance force (FOOB). Thus, the masses undergoing acceleration produce a collective force equal to and opposite of the out-of-balance force (FOOB). Specifically, as illustrated in
The calculated motion of the suspended mass, e.g., at the center of gravity (CG) thereof, which is calculated rather than directly measured (e.g., where there is no measurement device positioned at the CG), may be referred to herein as a “virtual point amplitude.” In this regard, virtual point amplitudes are intended to refer to displacement or motion measurements at a location that does not include a measurement device. Virtual point amplitudes may generally be determined by estimation assuming wash tub 120 is a rigid body and knowing the dimensional configuration of wash tub 120. Notably, by using dimensional knowledge and making such assumptions, the position or motion of any point, including points away from the place where the measurement device is located, may be predicted based on the measured position or motion at the measured location. In this manner, washing machine appliance 100 need not include multiple measurement devices while still maintaining the motion of each point on wash tub 120. It should be appreciated that actual measured displacements or virtual point amplitudes or combinations thereof may be used according to various embodiments of the present subject matter.
Turning now to
For example,
The valve 202 and the nozzle 203 are stationary relative to the rotatable basket 122, such that the spray or jet of balance fluid 210 from the nozzle 203 will flow into the portion of the gutter 204, e.g., one or more of the fill zones 1, 2, and 3, which traverses the nozzle 203 while the valve 202 is opened. Put simply for the sake of illustration but without limitation, the timing of when and for how long the valve 202 is opened while the basket 122 is rotating controls which balance fluid chamber(s) 208 receive the fill of balance fluid 210 and in what proportion. Thus, which one or more of the plurality of balance fluid chambers 208 receives the fill of balance fluid 210 is determined by the portion of the rotation of the basket 122 during which the valve 202 is opened. For example, as shown in
In some embodiments of the present invention, the flow of the balance fluid 210 may be controlled by or in response to the measurement devices 190. For example, the measurement devices 190 may provide a simple binary signal, such as a TRUE/FALSE signal, for example, a high/low voltage at an output pin or a single bit in a serial digital transmission, to open and close the valve 202 of the balancing system 200.
In example embodiments, the one or more measurement devices 190 may measure or detect movement of the tub 120 as one or more displacement amplitudes using the accelerometer and a gyroscope. For example, the amplitudes A1, A2, and A3 may be measured and an average amplitude may be calculated as shown in
In one particular (non-limiting) example,
As mentioned above, before accelerating a wash load to the high speeds used for, e.g. a spin cycle, the controller 186 may maintain a constant speed of the basket 122, whereby the wash load is plastered. During this constant speed rotation, the effect of the imbalance 1000 on periodic motion may be measured using the amplitudes provided by the measurement device(s) 190. One of the amplitudes may be for a virtual point representing the motion at the center of gravity of the suspended mass.
The motion at the center of gravity of the suspended mass is used because the location of an imbalance 1000, whether it be located in the front, middle or rear of the basket 122, does not change the motion amplitude of the center of gravity very much. This relationship becomes increasingly strong as speed increases. At low speeds, the point least affected by the imbalance location may move, e.g. forward of the center of gravity CG because the external forces applied by springs, gaskets and dampers have more influence. Referring to
The process of active balancing will be performed while the basket 122 is spinning at a constant speed. At a given speed, the time it takes the basket 122 to complete one revolution is constant. The time to rotate is tPERIOD, or tP.
t
P=60/speedrpm[seconds]
Turning now to
t
FILL IDEAL
=t
P120°/360°=tP/3
As the speed of the basket 122 increases, the phase angle between the location of the maximum displacement of the basket 122 and the OOB load 1000 increases. At very low speeds, the OOB load 1000 and the maximum displacement are nearly in the same location and the phase angle approaches 0°. At very high speeds, such as above 800 RPM, the maximum displacement and the OOB load 1000 are opposite each other and the phase angle approaches 180°. For a given washing machine, this phase angle is a known function of, primarily, the speed and the direction the amplitude is measured in. The size of the wash load can have a smaller effect on the phase angle. The time it takes the basket to rotate through the phase angle, tPHASE, will be used in the calculation that determines when the nozzle 203 is aligned with the ideal fill range:
t
PHASE
=t
P(ϕOOB PHASE/360)
The process of turning the fill valve 202 on may be delayed by some amount for a number of reasons such as to account for error, to prevent over filling the gutter 204, or to provide finer control over the amount of balance fluid 210 added in one rotation of the basket 122. The delay time begins when the nozzle 203 is approximately aligned with the 120° fill range 216 and may be denoted by the speed dependent constant tSTART DELAY. It should be noted that the 120° fill range 216 is by way of example only, in other embodiments more than three balance fluid chambers 208 may be provided, in such embodiments the fill range 216 may be less than 120°, e.g., for four balance chambers 208, the fill range 216 may be about 90°, etc.
The contributions to the calculation of the end buffer angle or time tEND BUFFER may be similar to tSTART DELAY, but there is an additional constraint on the value of tEND BUFFER. The arc of rotation for the time the valve 202 is on should be centered on the point directly opposite the OOB load 1000. As mentioned above, the gutter 204 is divided into parts, e.g., by dams 206, such that each part drains into a corresponding one of the plurality of balance fluid chambers 208 so that two chambers 208 can receive fluid 210 during the balancing. If the portion of the gutter 204 corresponding to one chamber 208 (e.g., one of the fill zones 1, 2, and 3 illustrated in
To calculate the nozzle on-time, tON, so that it is centered opposite the OOB mass:
t
ON
=t
FILL IDEAL−2*tSTART DELAY
where tEND BUFFER=tSTART DELAY.
Once the value of tSTART DELAY is established the value of tWAIT can be calculated. The effect of the angle ϕNOZZLE between the vector used to measure the amplitude (e.g., the measurement vector 217, as described above) and the location of the nozzle 203 is also needed and is represented by the speed dependent constant tNOZZLE.
t
NOZZLE
=t
P(ϕNOZZLE/360)
The next term accounts for the angle between the middle of the fill arc 216 and its ends. For example, in the illustrated embodiments where the fill arc 216 extends across 120°, the angle between the middle of the fill arc 216 and the ends thereof will be 60° (see, e.g.,
t
60
=t
P(60/360)
Using
t
WAIT
=t
PHASE
−t
NOZZLE
−t
60
+t
START DELAY
−t
AMP WAIT
In some embodiments, only the values of tWAIT and tON may be stored on the measurement device 190 to control the valve 202. Such embodiments may advantageously minimize the memory requirements for the control system 201, in particular for the measurement device 190. In some embodiments, e.g., when balancing is only performed at one speed, the values of tWAIT and tON may be stored as individual constants. In other embodiments, the values may be stored in a table when balancing is done at different speeds. In some embodiments, tWAIT and tON may not be stored as a value representing units of time, i.e. seconds. In such embodiments, the stored values may instead be proportional to the time they represent, e.g., tWAIT and tON may be integers scaled according to the clock rate used by the measurement device 190 microprocessor to perform the task of measuring tWAIT and tON.
As mentioned above, the measurement device 190 may be operationally independent of the controller 186. For example, in some embodiments, the controller 186 may not require a signal from the measurement device 190 to control the fill nozzle 202 signal 187. The controller 186 will continue to use the previously defined amplitude data from the measurement device 190 to additionally determine if active balancing should take place. Similarly, the measurement device 190 may not require a signal from the controller 186 to determine when to turn the fill nozzle 202 on and off. The measurement device 190 may be configured by the controller 186 prior to the fluid balancing operation.
Returning to
Turning now to
As illustrated in
Turning now to
Turning now to
After tON has elapsed, e.g., when the ON counter reaches tON as illustrated for example at 330 in
As mentioned above, the process of measuring the sequence of two time periods begins when software of the measurement device 190 determines that a new displacement amplitude of a designated sign, either positive or negative, has occurred. In some embodiments, the amplitude measures the periodic radial motion of the approximate center of gravity of the suspended mass of the washing machine appliance calculated using a virtual point, e.g., a virtual point amplitude, as described above. In other embodiments, the displacement amplitude may be directly measured, e.g., when the measurement device 190 is located approximately near the center of gravity. In at least some embodiments, the measurement device 190 only activates the valve 202 of the balancing system 200, e.g., provides an external TRUE signal 322, while the measurement device 190 is performing the measurement of the second time period tON. Additionally, the measurement device 190 TRUE signal may coincide with an orientation of the spinning wash basket that causes the fill nozzle 203 of the balancing system 200 to deliver balance fluid 210 to one or more selected balance fluid chambers 208 over an arc centered opposite the unbalanced wash load 1000 in the basket 122. For example, the measurement device 190 sends an external signal 322 in the TRUE state for a rotation angle of 120° or less if there are three balancing fluid chambers 208. In other embodiments, e.g., when there are four equally spaced balancing fluid chambers 208, the external signal 322 remains in the TRUE state for a rotation angle of 90° or less.
In some embodiments, the method 300 may also include a decision to stop filling. For example, as illustrated in
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
