The present disclosure is generally directed to suction motors and more specifically to magnetic transmissions for a suction motor.
Powered devices, such as vacuum cleaners, have multiple components that each receive electrical power from one or more power sources (e.g., one or more batteries or electrical mains). For example, a vacuum cleaner generally includes a suction motor assembly to generate a vacuum within a cleaning head. The suction motor assembly includes a motor and a suction body (e.g., an impeller such as an axial or radial impeller). The suction body can be directly coupled to a drive shaft of the motor such that the suction body rotates with the drive shaft. Rotation of the suction body causes a vacuum to be generated. The generated vacuum causes at least a portion of debris deposited on a surface to be cleaned to become entrained within an airflow extending into the vacuum cleaner such that at least a portion of the entrained debris can be deposited in, for example, a debris collector.
Universal motors are often used in powered devices, including vacuum cleaners. Consumers benefit from a cleaning device that has high suction, but are limited by the amount of power available to a motor using a household current or battery. Moreover, when a suction body is directly coupled to the motor, the speed of the suction body and the suction it generates is dictated by the speed of the motor.
A transmission between the motor and the suction body allows the two components to operate at differing speeds. However, mechanical transmissions operating at high speeds may not cost effective—both mechanical wear on transmission parts and the required precision in manufacturing may make use of a mechanical speed increase transmission impractical.
An example of a suction motor assembly, consistent with the present disclosure, may include a motor, a suction body (e.g., an impeller such as an axial or radial impeller), and a magnetic transmission configured to transfer rotational motion from the motor to the suction body.
In some instances, the magnetic transmission may include a low speed rotor coupled to the motor and a high speed rotor coupled to the suction body. In some instances, the low speed rotor may include a plurality of low speed rotor magnets and the high speed rotor may include one or more high speed rotor magnets. In some instances, the magnetic transmission may further include a support structure having a plurality of ferromagnetic structures. In some instances, the ferromagnetic structures may be configured to modulate magnetic fields generated by the plurality of low speed rotor magnets. In some instances, the magnetic transmission may further include a stator. In some instances, the motor may be configured cause the low speed rotor to rotate at a first rotational speed and the low speed rotor and the high speed rotor are configured such that the high speed rotor rotates at second rotational speed, the second rotational speed measuring greater than the first rotational speed. In some instances, the low speed rotor may further include an aerodynamic element. In some instances, the low speed rotor and the high speed rotor may be counter rotating. In some instances, the high speed rotor may be one of a salient pole rotor or an inductive rotor.
An example of a surface treatment apparatus, consistent with the present disclosure, may include a debris collector and a suction motor assembly. The suction motor assembly may include a motor, a suction body (e.g., an impeller such as an axial or radial impeller), and a magnetic transmission configured to transfer rotational motion from the motor to the suction body.
In some instances, the magnetic transmission may include a low speed rotor coupled to the motor and a high speed rotor coupled to the suction body. In some instances, the low speed rotor may include a plurality of low speed rotor magnets and the high speed rotor may include one or more high speed rotor magnets. In some instances, the magnetic transmission may further include a support structure having a plurality of ferromagnetic structures. In some instances, the ferromagnetic structures may be configured to modulate magnetic fields generated by the plurality of low speed rotor magnets. In some instances, the magnetic transmission may further include a stator. In some instances, the motor may be configured cause the low speed rotor to rotate at a first rotational speed and the low speed rotor and the high speed rotor may be configured such that the high speed rotor rotates at second rotational speed, the second rotational speed measuring greater than the first rotational speed. In some instances, the low speed rotor may further include an aerodynamic element. In some instances, the low speed rotor and the high speed rotor may be counter rotating. In some instances, the high speed rotor may be one of a salient pole rotor or an inductive rotor.
These and other features and advantages will be better understood by reading the following detailed description, taken together with the drawings wherein:
The present disclosure is generally directed to a suction motor assembly. The suction motor assembly may be configured to be used with a surface cleaning apparatus (e.g., a vacuum cleaner such as an upright vacuum cleaner, a handheld vacuum cleaner, a robotic vacuum cleaner, and/or any other surface cleaning apparatus). For example, in a surface cleaning apparatus, the suction motor assembly can be configured to generate a suction force at an inlet of the surface cleaning apparatus such that debris can be drawn into the inlet.
The suction motor assembly may include a motor, a suction body (e.g., an impeller such as an axial or radial impeller), and a magnetic transmission configured to transfer rotational motion from the motor to the suction body. Rotation of the suction body urges air to flow along an airflow path, wherein a portion of the airflow path extends through the suction motor assembly. Air flowing along the airflow path may have debris entrained therein. At least a portion of the entrained debris may be deposited in a debris collector of the surface cleaning apparatus before air flowing along the airflow path passes through the suction motor assembly.
A suction force generated by the suction motor assembly may be limited by the amount of power available to the motor using a household current or battery, and further by the speed of the suction body that is rotated by the motor.
Universal motors can be used in powered devices, including vacuum cleaners. Universal motors may reach peak efficiency around 40 thousand revolutions per minute (krpm) and may develop the most power at around 10-25 krpm. Efficiency of a suction body may increase as a size of the suction body is decreased and a rotational speed of the suction body is increased. For example, a reduction in the size of a suction body from a 110 millimeter (mm) diameter to a 65 mm diameter would increase efficiency; however, the rotational speed of the suction body may need to increase in order to optimally use the power available from the same motor. As such, in some instances, the suction body and the motor may have different rotational speeds. For example, for a 600-1200 Watt (W) universal motor operating at 10-25 krpm (e.g., as measured at a drive shaft of the motor), a 45 mm suction body may spin at approximately 100 krpm in order to optimize the efficiency of the suction body. To facilitate the different rotational speeds a transmission may be used to transfer rotational motion from the motor to the suction body, wherein the transmission is configured such that the suction body rotates faster than the motor. Mechanical transmissions operating at high speeds may not be cost effective—both mechanical wear on transmission parts and the required precision in manufacturing may make using a mechanical transmission impractical.
In an embodiment, the suction motor assembly includes a transmission incorporating a plurality of magnetic rotors. The suction motor assembly includes a motor and a suction body. A transmission transfers rotational motion from the motor to the suction body. The transmission includes a first and a second rotor. The first rotor is directly coupled to the motor (e.g., to a drive shaft of the motor). The second rotor is coupled to the suction body. Magnets are affixed to the first rotor such that the magnets rotate relative to (e.g., around) ferromagnetic structures fixed into a support structure. The ferromagnetic structures orient the magnetic fields that are generated by the magnets affixed to the first rotor as it rotates. The magnetic fields oriented by the ferromagnetic structures then interact with the second rotor. The interaction between magnets fixed in the second rotor and the magnetic fields transmitted by the ferromagnetic structures causes the second rotor to rotate around a rotation axis (e.g., a central axis) defined by the first rotor. The second rotor drives the rotation of the suction body. As such, the first and second rotors and ferromagnetic structures may generally be described as cooperating to form a magnetic transmission. A magnetic transmission allows torque generated by the motor to be transmitted from the first rotor to the second rotor without physical contact between the first and second rotors. The magnetic transmission can be constructed to be a speed increasing transmission such that the rotational speed of the suction body is greater than the rotational speed of the motor (e.g., as measured at a drive shaft of the motor).
In another embodiment, the suction motor assembly includes a transmission incorporating a plurality of rotors and a stator including magnetic elements. The suction motor assembly includes a motor and a suction body. A transmission is configured to transfer rotational motion from the motor to the suction body. The transmission includes a first rotor and a second rotor. The first rotor is directly coupled to the motor (e.g., to a drive shaft of the motor). The second rotor is coupled to the suction body. A fixed stator surrounds the first rotor, the fixed stator including a plurality of magnetic elements. Ferromagnetic structures are affixed to the first rotor such that as the first rotor is driven by the motor, they interact with magnets within the surrounding stator. The ferromagnetic structures orient the magnetic fields that are generated by the magnetic elements of the stator. The magnetic fields oriented by the ferromagnetic structures then interact with magnets of the second rotor. The interaction between magnets of the second rotor and the magnetic fields transmitted by the ferromagnetic structures causes the second rotor to rotate around a rotation axis (e.g., a central axis) defined by the first rotor. The second rotor drives the rotation of the suction body. As such, the first and second rotors and ferromagnetic structures may generally be described as cooperating to form a magnetic transmission. A magnetic transmission allows torque generated by the motor to be transmitted from the first rotor to the second rotor without physical contact between the first and second rotors. The magnetic transmission can be constructed to be a speed increasing transmission such that the rotational speed of the suction body is greater than the rotational speed of the motor (e.g., as measured at a drive shaft of the motor).
As used herein “first rotor,” “low speed rotor,” “primary rotor,” “input rotor”, or “drive rotor” refer to a rotor coupled (e.g., directly coupled) to the motor. As used herein “second rotor,” “high speed rotor,” “secondary rotor,” “output rotor”, or “driven rotor” refer to a rotor coupled (e.g., directly coupled) to the suction body. As used herein “irons,” “iron arcs,” or “iron pins” refer to any array of ferromagnetic structures used to transmit magnetism between at least two rotors.
Although specific embodiments of the suction motor assembly using radial flux are shown, other embodiments of the suction motor assembly using axial flux are within the scope of the present disclosure.
The first rotor 5 and the second rotor 6 can be configured such that the transmission 4 is a non-contact transmission. A non-contact transmission may generally be described as a transmission in which rotational motion is transferred directly between at least a first component (e.g., the first rotor 5 or the second rotor 6) and a second component (e.g., the other of the first rotor 5 or the second rotor 6) without physical contact between the first and second components. For example, the first rotor 5 may be configured to transfer rotational motion to the second rotor 6 through the interaction between magnetic fields extending from the first rotor 5 and the second rotor 6. In this example, the transmission 4 may generally be referred to as a magnetic transmission.
The vacuum assembly 10 includes a debris collector 14 and the suction motor assembly 1 of
Referring to
The motor 101 is configured to cause the low speed rotor 103 to rotate. For example, the low speed rotor 103 can be coupled to a drive shaft of the motor 101. The rotation of the low speed rotor 103 causes the low speed rotor permanent magnets 113 to rotate around the support structure 104. The ferromagnetic structures of the support structure 104 modulate the magnetic fields generated by the low speed rotor permanent magnets 113 and thereby transmit the magnetic forces to the high speed rotor permanent magnets 116. The interactions of the magnetic fields of the low speed rotor permanent magnets 113 and the high speed rotor permanent magnets 116 results in a magnetic coupling such that a rotation of the low speed rotor 103 causes the high speed rotor 106 to rotate at a rotational speed that measures greater than the rotational speed of the low speed rotor 103.
As shown in
Although the magnetic transmission is shown as having seven pairs of low speed rotor permanent magnets 213 and eight ferromagnetic structures 205, different configurations may be used to transmit torque from a low speed rotor to a high speed rotor, thereby creating an asynchronous magnetic transmission.
Different permutations of primary rotors and iron pin arrays produce differing transmission ratios and rotational directions. The four pair primary rotor 352 paired with iron pin arrays including the support structure 354 having the three iron arcs or the support structure 355 having the three iron pins produces a 1:4 transmission ratio and a non-reversing transmission coupling. That is, for every turn of the primary rotor 352, 353, the secondary rotor 351 completes approximately four turns in the same direction as the primary rotor. The four pair primary rotor 352 paired with the support structure 356 having the five iron pin array produces a 1:4 transmission ratio and a reversing transmission coupling. The seven pair primary rotor 353 paired with the support structure 357 having the six iron pin array produces a 1:7 transmission ratio and a non-reversing transmission coupling. The seven pair primary rotor 353 paired with the support structure 358 having the eight iron pin array produces a 1:7 transmission ratio and a reversing transmission coupling. Permutations of the configurations may be used depending on the diameter of a suction body and the desired speed for the suction body.
In addition to providing asynchronous speeds to increase efficiency, magnetic transmissions provide further benefits to a suction motor assembly. As shown in
When motors are used in handheld or other consumer appliances, minimizing the gyroscopic effect generated, using the magnetic transmission, may improve the usability of a device. Specifically, it may reduce the amount of angular momentum felt by a user, thus potentially decreasing the effort required to stabilize the device while it is in use.
As further shown in
The magnetic transmission 708 shown provides for the fixed field of the stator 713 and uses the low speed rotor 703 as a transmitting element to the high speed rotor 706. Rotation of the motor 701 causes rotation of the low speed rotor 703. During operation of the motor 701, the plurality of electromagnets of the stator 713 are powered and generate a magnetic field. The rotation of the low speed rotor 703 causes the low speed rotor 703 to rotate within the stator 713. The ferromagnetic structures 733 of the low speed rotor 703 modulate the magnetic fields generated by the plurality of electromagnets within the stator 713 and thereby transmit the magnetic forces to the high speed rotor 706. The high speed rotor 706 may be formed using one or more permanent magnets, using a salient pole rotor, or by using an inductive rotor. The transmission of magnetic force from the plurality of electromagnets within the stator 713 to the high speed rotor 706 using the low speed rotor 703 produces an asynchronous magnetic coupling, allowing for the transfer of torque and causing the high speed rotor 706 to rotate at a different (e.g., greater) speed than the low speed rotor 703.
As described above, the high speed rotor 706 may be formed using one or more permanent magnets, using a salient pole rotor, or by using an inductive rotor. A magnetic transmission that uses one or more permanent magnets in the high speed rotor 706 would allow the highest efficiency and torque transmission. However, permanent magnets can be expensive and can be brittle. A salient pole rotor (asymmetrical iron that follows the field's rotation because it serves as a bridge for the field) would have reduced efficiency, but still provide the desired increased speed transmission at a lower cost than the permanent magnets. An inductive rotor, such as a squirrel cage, may be used as the high speed rotor. The inductive rotor would have reduced efficiency as compared to the permanent magnets, but would prevent decoupling between the low speed rotor 703 and the high speed rotor 706.
The term “coupled” as used herein refers to any connection, coupling, link or the like by which torque input by one system element is imparted to the “coupled” element. Such “coupled” devices, may be, but are not necessarily directly connected to one another and may be separated by intermediate components or devices that may manipulate or modify such coupled elements. Likewise, the terms “connected” or “coupled” as used herein in regard to mechanical or physical connections or couplings is a relative term and may include, but does not require, a direct physical connection.
Elements, components, modules, and/or parts thereof that are described and/or otherwise portrayed through the figures to communicate with, be associated with, and/or be based on, something else, may be understood to so communicate, be associated with, and/or be based on in a direct and/or indirect manner, unless otherwise stipulated herein.
Unless otherwise stated, use of the word “substantially” or “approximately” may be construed to include a precise relationship, condition, arrangement, orientation, and/or other characteristic, and deviations thereof as understood by one of ordinary skill in the art, to the extent that such deviations do not materially affect the disclosed methods and systems. Throughout the entirety of the present disclosure, use of the articles “a” and/or “an” and/or “the” to modify a noun may be understood to be used for convenience and to include one, or more than one, of the modified noun, unless otherwise specifically stated. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
While the principles of the invention have been described herein, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation as to the scope of the invention. Other embodiments are contemplated within the scope of the present invention in addition to the exemplary embodiments shown and described herein. It will be appreciated by a person skilled in the art that a surface cleaning apparatus may embody any one or more of the features contained herein and that the features may be used in any particular combination or sub-combination. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention.
The present application claims the benefit of U.S. Provisional Application Ser. No. 62/878,428 filed on Jul. 25, 2019, entitled Suction Motor Assembly with Magnetic Transmission, which is fully incorporated herein by reference.
Number | Date | Country | |
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62878428 | Jul 2019 | US |