Laundry treating appliance with method to reduce drum excursions

Abstract

 A laundry treating appliance and method for reducing drum (30) excursions associated with the forming a liquid inertial mass (63, LIM) in the tub (34) prior to an extraction phase during a cycle of operation.

Description

BACKGROUND OF THE INVENTION

[0001] Laundry treating appliances, such as a washing machine, may have a rotatable drum in which laundry may be placed for treatment. The rotatable drum, defining a treating chamber, resides within a liquid holding tub, which may be mounted by a suspension system to a cabinet. In such a configuration, the tub and drum, including any contents, form a suspended mass subject to the damping forces of the suspension. In cases where the laundry is non-uniformly distributed in the rotating drum, the rotating drum may be in the imbalance condition, which may lead to movement of the suspended mass, especially at higher rotational speeds and/or at rotational speeds corresponding to known dynamic modes of the appliance, such as pendulum mode, where the suspended mass tends to swing back and forth like a pendulum, which may cause the appliance to rock, and a vertically rocking/bouncing mode, where the appliance essentially jumps up and down. The rocking and jumping modes typically make undesirable noise and are not desired by the consumer.

SUMMARY OF THE INVENTION

[0002] The invention relates to a laundry treating appliance and method for forming a liquid inertial mass in the tub by providing a predetermined amount of liquid to the tub, and executing an extraction phase by accelerating the rotational speed of the drum toward an extraction speed while the liquid inertial mass is in the tub at least for a portion of the extraction phase.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] In the drawings:

[0004] FIG. 1 is a schematic cross-sectional view of a laundry treating appliance according to one embodiment of the invention.

[0005] FIG. 2 is a schematic representation of a controller for controlling the operation of one or more components of the laundry treating appliance of FIG. 1.

[0006] FIG. 3 schematically illustrates the presence of the liquid inertial mass within the tub, according to one embodiment of the invention.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0007] FIG. 1 illustrates a laundry treating appliance in the form of a washing machine 10 according to one embodiment of the invention. The laundry treating appliance may be any machine that treats articles such as clothing or fabrics. Non-limiting examples of the laundry treating appliance may include a top loading/vertical axis washing machine; a front loading/horizontal washing machine; a combination washing machine and dryer; and a refreshing/revitalizing machine. The washing machine 10 described herein shares many features of a traditional automatic washing machine, which will not be described in detail except as necessary for a complete understanding of the invention.

[0008] Washing machines are typically categorized as either a vertical axis washing machine or a horizontal axis washing machine. As used herein, the "vertical axis" washing machine refers to a washing machine having a rotatable drum, perforate or imperforate, that holds fabric items and a clothes mover, such as an agitator, impeller, nutator, and the like within the drum. The clothes mover moves within the drum to impart mechanical energy directly to the clothes or indirectly through liquid in the drum. The liquid may include one of wash liquid and rinse liquid. The wash liquid may have at least one of water and a wash aid. Similarly, the rinse liquid may have at least one of water and a wash aid. The clothes mover may typically be moved in a reciprocating rotational movement. In some vertical axis washing machines, the drum rotates about a vertical axis generally perpendicular to a surface that supports the washing machine. However, the rotational axis need not be vertical. The drum may rotate about an axis inclined relative to the vertical axis. As used herein, the "horizontal axis" washing machine refers to a washing machine having a rotatable drum, perforate or imperforate, that holds fabric items and washes the fabric items by the fabric items rubbing against one another as the drum rotates. In some horizontal axis washing machines, the drum rotates about a horizontal axis generally parallel to a surface that supports the washing machine. However, the rotational axis need not be horizontal. The drum may rotate about an axis inclined relative to the horizontal axis. In horizontal axis washing machines, the clothes are lifted by the rotating drum and then fall in response to gravity to form a tumbling action. Mechanical energy is imparted to the clothes by the tumbling action formed by the repeated lifting and dropping of the clothes. Vertical axis and horizontal axis machines are best differentiated by the manner in which they impart mechanical energy to the fabric articles. The illustrated exemplary washing machine of FIG. 1 is a vertical axis washing machine.

[0009] As illustrated in FIG. 1, the laundry treating appliance 10 may include a housing 14, which may be a cabinet or a chassis and/or a frame to which decorative panels may or may not be mounted. The cabinet may be defined by a front wall 16, a rear wall 18, and a pair of side walls 20 supporting a top wall 22. A user interface 24 may be included on the housing 14 and may have one or more knobs, switches, displays, and the like for communicating with the user, such as to receive input and provide output. A door or lid 28 may be operably coupled with the housing 14 and may be selectively moveable between opened and closed positions to close an opening in a top wall 22 of the housing 14, which provides access to the interior of the housing 14.

[0010] A rotatable drum 30 having an open top may be disposed within the interior of the housing 14 and may define a treating chamber 32 for treating laundry. An imperforate tub 34 may also be positioned within the housing 14 and may define an interior within which the drum 30 may be positioned. The tub 34 may be supported within the cabinet by a suitable suspension system 35. The suspension system 35 may include multiple strut assemblies 36 extending from the housing 14 to the tub 34. The drum 30 may include a plurality of perforations 37 such that liquid may flow between the tub 34 and the drum 30 through the perforations 37. While the illustrated laundry treating appliance 10 includes both the tub 34 and the drum 30, with the drum 30 defining the laundry treatment chamber 32, it is within the scope of the invention for the laundry treating appliance to include only one receptacle, with the receptacle defining the laundry treatment chamber for receiving the load to be treated.

[0011] A clothes mover 38 may be located in the drum 30 to impart mechanical agitation to a load of laundry placed in the drum 30. The drum 30 and the clothes mover 38 may be driven by an electrical motor 40 operably coupled with the drum 30 and clothes mover 38. A clutch assembly 41 may be provided to selectively operably couple the motor 40 with either the drum 30 and/or the clothes mover 38. The clothes mover 38 may be oscillated or rotated about its axis of rotation during a cycle of operation in order to produce high water turbulence effective to wash the load contained within the treating chamber 32. The motor 40 may rotate the drum 30 at various speeds in either rotational direction about an axis of rotation.

[0012] A liquid supply system may be provided to liquid, such as water or a combination of water and one or more wash aids, such as detergent, into the treating chamber 32. The liquid supply system may include a water supply configured to supply hot or cold water. The water supply may include a hot water inlet 44 and a cold water inlet 46, a valve assembly, which may include a hot water valve 48, a cold water valve 50, and a diverter valve 55, and various conduits 52, 56, 58. The valves 48, 50 are selectively openable to provide water, such as from a household water supply to the conduit 52. The valves 48, 50 may be opened individually or together to provide a mix of hot and cold water at a selected temperature. While the valves 48, 50 and conduit 52 are illustrated exteriorly of the housing 14, it may be understood that these components may be internal to the housing 14.

[0013] As illustrated, a detergent dispenser 54 may be fluidly coupled with the conduit 52 through a diverter valve 55 and a first water conduit 56. The detergent dispenser 54 may include means for supplying or mixing detergent to or with water from the first water conduit 56 and may supply such treating liquid to the tub 34. It has been contemplated that water from the first water conduit 56 may also be supplied to the tub 34 through the detergent dispenser 54 without the addition of a detergent. A second water conduit, illustrated as a separate water inlet 58, may also be fluidly coupled with the conduit 52 through the diverter valve 55 such that water may be supplied directly to the treating chamber 32 through the open top of the drum 30. Additionally, the liquid supply system may differ from the configuration shown, such as by inclusion of other valves, conduits, wash aid dispensers, heaters, sensors such as a liquid level sensor, a weight sensor, a motor torque sensor, a temperature sensor, a transducer such as potentiometer, and the like, to control the flow of treating liquid through the laundry treating appliance 10 and for the introduction of more than one type of detergent/wash aid.

[0014] A liquid recirculation system may be provided for recirculating liquid from the tub 34 into the treating chamber 32. More specifically, a sump 60 may be located in the bottom of the tub 34 and the liquid recirculation system may be configured to recirculate treating liquid from the sump 60 onto the top of a laundry load located in the treating chamber 32. A liquid remover in the form of a pump 62 may be housed below the tub 34 and may have an inlet fluidly coupled with the sump 60 and an outlet configured to fluidly couple to either or both a household drain 64 or a recirculation conduit 66. In this configuration, the pump 62 may be used to drain or recirculate wash water in the sump 60. As illustrated, the recirculation conduit 66 may be fluidly coupled with the treating chamber 32 such that it supplies liquid into the open top of the drum 30. The liquid recirculation system may include other types of recirculation systems.

[0015] The laundry treating appliance 10 may further include a controller 70 coupled with various working components of the laundry treating appliance 10 to control the operation of the working components. As illustrated in FIG. 2, the controller 70 may be provided with a memory 72 and a central processing unit (CPU) 74. The memory 72 may be used for storing the control software that may be executed by the CPU 74 in completing a cycle of operation using the laundry treating appliance 10 and any additional software. The memory 72 may also be used to store information, such as a database or table, and to store data received from the one or more components of the laundry treating appliance 10 that may be communicably coupled with the controller 70.

[0016] The controller 70 may be operably coupled with one or more components of the laundry treating appliance 10 for communicating with and/or controlling the operation of the components to complete a cycle of operation. For example, the controller 70 may be coupled with the hot water valve 48, the cold water valve 50, diverter valve 55, and the detergent dispenser 54 for controlling the temperature and flow rate of treating liquid into the treating chamber 32; the pump 62 for controlling the amount of treating liquid in the treating chamber 32 or sump 60; the motor 40 and clutch 41 for controlling the direction and speed of rotation of the drum 30 and/or the clothes mover 38; and the user interface 24 for receiving user selected inputs and communicating information to the user. The controller 70 may also receive input from the liquid level sensor 76, which may be operably coupled to the tub 34 to detect the liquid level in the tub 34 and transmit the signal to the controller 70 such that the amount of liquid may be selectively controlled in the tub 34 during a cycle of operation. The controller 70 may also receive input from various additional sensors 78, which are known in the art and not shown for simplicity. Non-limiting examples of additional sensors 78 that may be communicably coupled with the controller 70 include: weight sensors, motor torque sensors, temperature sensors, and transducers such as a potentiometers.

[0017] The laundry treating appliance 10 may perform one or more manual or automatic treating cycles or cycle of operation. A common cycle of operation includes a wash phase, a rinse phase, and a spin extraction phase. Other phases for cycles of operation include, but are not limited to, intermediate extraction phases, such as between the wash and rinse phases, and a pre-wash phase preceding the wash phase, and some cycles of operation include only a selected one or more of these exemplary phases.

[0018] The drum 30, tub 34, clothes mover 38, motor 40 and any liquid or laundry in the treating chamber 32 and tub 34 may be thought of as a mass that is suspended from the housing 14 by the suspension system 35, which is illustrated by the struts 36. The suspension system 35 will have various dynamic modes that may change depending on the rotational speed of the drum, especially when laundry resides within the treating chamber 32, and more especially when the laundry is non-uniformly distributed relative to the rotational axis and forms an imbalance.

[0019] During an operation of the laundry treating appliance, the drum may rotate in accordance with a cycle of operation. In case the laundry is non-uniformly distributed in the drum 30, the laundry imbalance during the rotation of the drum 30 may induce the drum 30 to deviate off an anticipated rotational orbit and move the drum 30 in a side-to-side direction, which may be referred to as the pendulum mode because the suspended mass is essentially swinging back and forth on the struts 34 within the housing 14. Such back and forth swinging may result in laundry treating appliance 10 "walking" on the floor on which the laundry treating appliance is located and/or the drum 30 may collide with the surrounding tub 34 and/or housing 14 to generate uncomfortable noise or even incur physical damage such as wear to the tub 34 and/or cabinet dents.

[0020] The rotational speed of the drum 30 at which the pendulum mode is present is typically a function of the structure of the specific machine. For the illustrated machine, the pendulum mode occurs between 50-90 rpm as the drum 30 transitions to speeds where the laundry tends to "satellize" with the drum 30. That is, the centrifugal force applied to the laundry is sufficient for the laundry to "stick" to the drum 30 and not move. The pendulum mode tends to correspond to the first natural frequency of the suspended mass.

[0021] A vertical travel mode is another dynamic mode that occurs when the suspended mass starts reciprocating up and down, which in severe cases may cause part of the suspended mass to contact the cabinet, causing related movement laundry treating appliance 10.

[0022] The rotational speed of the drum 30 at which the vertical travel mode occurs is also machine-dependent. For the illustrated machine, the vertical travel mode occurs around 170-240 rpm. The vertical travel mode tends to correspond to the second natural frequency of the suspended mass.

[0023] Once at least one of these modes becomes significant during a cycle of operation, the user generally may need to stop the operation of the laundry treating appliance 10 to redistribute the laundry in the drum 30 followed by re-starting the operation, which may take an extended washing cycle time and results in a customer unsatisfaction. Alternatively, the user may relieve a portion of the laundry of the laundry treating appliance 10 to treat the portion of the laundry next time.

[0024] The invention addresses the problems associated with these different dynamic modes by creating a liquid inertial mass in the tub 34 during the pendulum mode and removing the liquid inertial mass, if present, prior to the vertical travel mode. The liquid inertial mass tends to retard the movement of the tub during the pendulum mode, but may exacerbate the vertical travel mode.

[0025] FIG. 3 schematically illustrates the presence of the liquid inertial mass 63 within the tub 34. The liquid inertial mass 63 may be used any time during the cycle of operation where the drum 30 is to be rotated, especially at low speed ranges, for example, less than 200 rpm. It is generally understood that some exemplary phases such as the pre-wash phase, the wash phase and the rinse phase may be followed by an extraction phase during which the liquid is drained from the laundry or the tub 34. The extraction phase may be generally conducted by centrifugally rotating the drum 30 about a rotational axis to a predetermined spin speed for a predetermined time period such that practically all of the liquid may be removed out of the tub 34 according to a cycle of operation. The liquid inertial mass 63 is particularly useful during an extraction phase, especially where low drum rotational speeds are maintained.

[0026] The formation of the liquid inertial mass 63 may be done in any suitable manner. Liquid can be supplied directly to the tub 34 whenever it is desired to form the liquid inertial mass 63. In order to conserve liquid consumption, the liquid inertial mass 63 may be formed from liquid already present in the tub 34. Advantageously, most extraction phases occur after liquid is already provided in the tub 34 for the corresponding cycle of operation. Therefore, the liquid already present in the tub 34 may be used to form the liquid inertial mass 63. If the liquid present is insufficient to form the desired liquid inertial mass 63, then more liquid is added to the already present liquid. If too much liquid is present for the liquid inertial mass 63, then some of the present liquid is removed from the tub 34 until the desired amount of liquid remains for the liquid inertial mass 63.

[0027] An illustrative example in the context of an extraction phase in a wash cycle should prove useful in understanding the use of the liquid inertial mass 63. When the wash phase is completed for the laundry (not shown) in the tub 34, in many cases there will be more liquid present in the tub 34 than is required for the liquid inertial mass 63. This liquid is illustrated in FIG. 3 as the wash level, WL. Thus, a portion of the wash liquid may be removed from the tub 34 by activating the liquid remover such as the pump 62 for a predetermined time. The amount of the residual liquid may be monitored in terms of the liquid level using the liquid level sensor 76. Alternatively, other sensors such as the weight sensor may be used in conjunction with one or more control software in calculating the amount of the residual liquid.

[0028] When the level of residual liquid goes down to the level, LIM, suitable for the liquid inertial mass 63, the pump 62 may deactivate, and the inlet and outlet of the pump 62 may be configured to be closed to maintain the LIM. Then, the extraction phase may begin by increasing the rotational spin speed of the drum 30 up to an intermediate spin speed, for example 30 rpm, for a dwell for a predetermined time period, followed by increasing up to a threshold spin speed, for example 100-125 rpm, for another dwell for a predetermined time period. It may be understood that the spin speed and/or dwell time for the intermediate spin step and the threshold spin step may vary, depending on the configuration of the laundry treating appliance 10.

[0029] In accelerating from 30 rpm to 100-125 rpm, the rotational speed of the drum 30 passes through the speed range where the suspended mass is subject to the pendulum mode. The liquid inertial mass 63 in the form of the residual liquid in the tub 34 tends to retard the movement of the suspended mass as it passes through the pendulum mode because of the increased inertial of the suspended mass. Another benefit of the liquid inertial mass 63, unlike solid material, is that the liquid inertial mass 63 may not immediately respond to an applied force. Instead, the liquid inertial mass 63 may lag behind to compensate for the tub/drum movements that may be observed in the tub 34 that does not hold any residual liquid during spinning. As a result, for the same degree of imbalance, suspended mass will have less movement during the pendulum mode.

[0030] After the dwell at 100-125 rpm, where imbalances are typically detected, the drum 30 is normally accelerated to an extraction speed, which is often greater than 500 rpm, and necessarily passes through the vertical travel mode. When passing through the vertical travel mode, the presence of the liquid inertial mass 63 is not desired because the extra mass will make it more likely that the suspension system 35 will reach its limit and bottom out. Thus, prior to accelerating to speeds associated with the vertical travel mode, the liquid inertial mass 63 may be removed from the tub 34, such as by activating the pump 62 to drain the liquid inertial mass 63 from the tub 34. The drum 30 may then be accelerated through the speed range where the vertical travel mode is encountered. It is contemplated that the liquid inertial mass 63 will be drained during the dwell at 100-125 rpm so that the presence of the liquid inertial mass 63 does not interfere with imbalance detection.

[0031] While the LIM may be satisfied by removing a certain amount of liquid that is initially supplied to the tub 34, it is also noted that the LIM may be satisfied by adding liquid 63 to the tub 34 from outside the tub 34. For example, it may be understood that the laundry may be sometimes treated in a recirculating wash phase, where the liquid is recirculated from the sump 60 through the recirculation circuit 66 to provide the liquid on top of the laundry, and generally less amount of liquid may be consumed than other wash phase such as a tumble wash phase where generally more liquid is required for treating laundry. It may be understood that the amount of liquid consumed for the recirculating wash phase may be less than the amount of liquid that is required to form the liquid inertial mass 63, and some amount of liquid may need to be added to the tub 34 from outside the tub 34 to compensate for the difference and to form the liquid inertial mass 63 to reduce drum excursions during spin.

[0032] The amount of liquid required for the liquid inertial mass 63 may be determined by the geometrical and functional constraints of the laundry treating appliance 10 which is in use for the laundry treatment, and may be different from one appliance to another. For example, the LIM may be determined to be below a level where an overflow out of the tub 34 does not occur during a cycle of operation. In another example, the LIM may be determined to be below a level below where rotating of the drum 30 will not generate sufficient suds that a suds lock may occur. In yet another example, the LIM may be determined to be below a level where a water ring may be generated between the drum 30 and tub 34 during an extraction phase.

[0033] It may be understood that the invention described here may not be limited to the wash phase in a cycle of operation. The invention may be used in conjunction with any phase such as pre-wash phase, wash phase, rinse phase, or other cycles of operations including one or more of these exemplary phases, which may followed by an extraction phase.

[0034] The invention described herein uses liquid inertial mass to compensate for any nonuniformity of the laundry distributed received in the drum of the laundry treating appliance, and minimizes the excursions of the drum and cabinet hits during a cycle of operation. As a result, the drum excursions and side-to-side walk of the laundry treating appliance can be prevented. The collision between the drum and the tub or housing can be also prevented; therefore, the noise generation can be also minimized. It is also noted that the invention may use liquid that is already being used in a cycle of operation for the treatment of the laundry, which incurs no additional cost.

Claims

1. A method of operating a laundry treating appliance (10) according to a cycle of operation, with the laundry treating appliance having a tub (34) and a rotatable drum (30) located within the tub, the method comprising:

forming a liquid inertial mass (63, LIM) in the tub (34) by providing a predetermined amount of liquid to the tub; and

executing an extraction phase by accelerating rotational speed of the drum (30) toward an extraction speed while the liquid inertial mass (63, LIM) is in the tub (34) at least for a portion of the extraction phase.

2. The method of claim 1 wherein the providing a predetermined amount of liquid to the tub (34) comprises at least one of supplying liquid to or draining liquid from liquid already present in the tub (34) until the predetermined amount is reached.

3. The method of claim 2 wherein the predetermined amount of liquid to the tub (34) comprises a predetermined level in the tub.

4. The method of claim 3 wherein the predetermined level is below a level in the tub (34) where rotation of the drum (30) during the extraction phase would generate sufficient suds to cause suds lock.

5. The method of claim 3 wherein the predetermined level is below a level in the tub (34) where rotation of the drum (30) during the extraction phase would generate a water ring about the drum.

6. The method of claim 3 wherein the predetermined level is below the drum (30).

7. The method of claim 2 wherein the liquid already present in the tub (34) comprises at least one of wash liquid and rinse liquid, the method further comprising a wash phase preceding the extraction phase and the wash liquid is provided during the wash phase, or comprising a rinse phase preceding the extraction phase and the rinse liquid is provided during the rinse phase.

8. The method of claim 1 wherein the liquid inertial mass (63, LIM) is present in the tub (34) when the rotational speed of the drum (30) reaches a natural frequency of the drum during the extraction phase, the natural frequency corresponding to a pendulum mode of the drum (30).

9. The method of claim 8 further comprising removing the liquid inertial mass (63) from the tub (34) after the natural frequency corresponding to the pendulum mode of the drum (30) and prior to the rotational speed of the drum reaching a natural frequency corresponding to a vertical travel mode of the drum (30) during the extraction phase.

10. The method of claim 1 further comprising removing the liquid inertial mass (63) from the tub (34) prior to the rotational speed of the drum (30) reaching a natural frequency corresponding to a vertical travel mode of the drum (30) during the extraction phase, the liquid inertial mass being removed by draining the liquid inertial mass from the tub (34).

11. A laundry treating appliance (10) comprising:

a chassis (14) defining an interior;

a tub (34) for holding liquid and located within the chassis interior;

a drum (30) defining a laundry treating chamber (32), located within the tub (34), and rotatable about an axis of rotation;

a motor (40) operably coupled to the drum (30) to effect the rotation of the drum;

a suspension system (35) coupling the tub (34) to the chassis (14);

a liquid supply (44, 46) fluidly coupled to at least one of the tub (34) and drum (30);

a liquid remover (62) fluidly coupled to the tub(34); and

a controller (70) operably coupled to and controlling the motor (40), liquid supply (44, 46, 48, 50), and liquid remover (62) to effect the formation of a liquid inertial mass (63) in the tub (34) by providing a predetermined amount of liquid to the tub (34), and accelerating rotational speed of the drum (30) toward an extraction speed while the liquid inertial mass (63) is in the tub (34).

12. The laundry treating appliance of claim 11 wherein the controller (70) controls the liquid supply (44, 46, 48, 50) and liquid remover (62) to ensure the presence of the liquid inertial mass (63) when the rotational speed of the drum (30) reaches a natural frequency of the drum corresponding to a pendulum mode of the drum (30).

13. The laundry treating appliance of claim 12 wherein the controller (70) controls the liquid remover (62) to remove the liquid inertial mass (63) from the tub (34) after the natural frequency corresponding to the pendulum mode of the drum (30) and prior to the rotational speed of the drum (30) reaching a natural frequency corresponding to a vertical travel mode of the drum (30) during an extraction phase.

14. The laundry treating appliance of claim 13 further comprising a liquid level sensor (76) operably coupled to the controller (70) and the controller effects the providing of the predetermined amount of liquid to the tub (34) by controlling the liquid supply (44, 46, 48, 50) and liquid remover (62) until the liquid reaches a predetermined level in the tub as sensed by the liquid level sensor (76).

15. The laundry treating appliance of claim 12 wherein the axis of rotation is a vertical axis of rotation, and the suspension comprises multiple struts (36) extending from the chassis (14) to the tub (34).

Drawing