The present invention relates to vacuum cleaners, and more particularly to diffusers for a motor-fan assembly for vacuum cleaners.
Vacuum cleaners typically include a base and a handle that pivots with respect to the base between an upright or storage position and an inclined position to allow the user to move the base of the vacuum cleaner along a surface to be cleaned. The base of the vacuum cleaner often includes a nozzle that defines an inlet. The handle of the vacuum cleaner often includes a motor-fan assembly that is operable to generate an airflow through the inlet. The airflow includes a mixture of air and debris from the surface to be cleaned. In many vacuum cleaners, the motor-fan assembly includes a diffuser for improving system efficiency. The diffuser includes vanes that cause an entering airflow to slow, which raises the static pressure of the airflow. Thus, the diffuser converts air velocity into static pressure rise. Although the diffuser improves the air performance of the system, the design of the vanes can create a high pitched whistle that is annoying to users of the vacuum cleaner. After the airflow passes through the vanes, it is directed to radially arranged vanes on the under side of the diffuser which further slows the airflow and further directs the airflow to the electric motor for cooling before exiting the vacuum cleaner.
In one embodiment, the invention provides a motor-fan assembly for a vacuum cleaner. The motor-fan assembly includes a fan, a motor including an output shaft coupled to the fan, the motor operable to rotate the fan, and a diffuser. The diffuser includes a disc, a wall that surrounds the disc, and a plurality of vanes that are coupled to an outer surface of the wall and extend radially outward from the outer surface of the wall. The disc has a first surface that faces towards the fan, a second surface that faces away from the first surface, and an aperture that extends through the disc between the first surface and the second surface. The output shaft extends through the aperture. The disc further includes an outer periphery that extends radially around the aperture. The wall surrounds the outer periphery of the disc. The wall has an inner surface that faces toward the output shaft and an outer surface that faces away from the inner surface.
In another embodiment the invention provides a vacuum cleaner that includes a dirt collection chamber, a base including a nozzle defining an inlet of the vacuum cleaner through which debris travels towards the dirt collection chamber, a handle coupled to the base and configured to move the base along a surface to be cleaned, and a motor-fan assembly operable to generate an airflow through the inlet and the dirt collection chamber. The motor-fan assembly includes a fan, a motor including an output shaft coupled to the fan, the motor operable to rotate the fan to generate the airflow, and a diffuser. The diffuser includes a disc, a wall that surrounds the disc, and a plurality of vanes that are coupled to an outer surface of the wall and extend radially outward from the outer surface of the wall. The disc has a first surface that faces towards the fan, a second surface that faces away from the first surface, and an aperture that extends through the disc between the first surface and the second surface. The output shaft extends through the aperture. The disc further includes an outer periphery that extends radially around the aperture. The wall surrounds the outer periphery of the disc. The wall has an inner surface that faces toward the output shaft and an outer surface that faces away from the inner surface.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.
Referring to
The cover 58 includes an inlet aperture 60. The housing 44 of the motor 42 includes an outlet aperture 48. The cover 58 is coupled to the housing 44 of the motor 42 to surround the fan 38 and the diffuser 50 so that the airflow generated by the motor-fan assembly 34 travels through the inlet aperture 60 and is exhausted through the outlet aperture 48 of the housing 44.
Referring to
Referring to
The plurality of vanes 70 are coupled to the outer surface 94 of the wall 66 and extend radially outward from the outer surface 94 of the wall 66. The vanes 70 are positioned between the first edge 63 and the second edge 64 of the wall 66 such that the vanes 70 do not extend past the edges 63 and 64 in the illustrated embodiment. In other embodiments, the vanes can extend past the edges 63 and 64. The plurality of vanes 70 are each airfoil-shaped. The airfoil-shaped vanes 70 each include a leading edge 102 and a trailing edge 106. A chord line 110 connects the leading edge 102 and the trailing edge 106 and forms an acute angle 116 with respect to a reference plane 114 that intersects the chord line 110 at the trailing edge 106 and is parallel to the first surface 74 of the disc 62. Another set of vanes 118 are coupled to the second surface 78 of the disc 62 and arranged circumferentially around the aperture 82. Although in the illustrated embodiment, the vanes 70 are airfoil-shaped, in other embodiments, the vanes can take other suitable shapes.
In operation, referring to
The motor-fan assembly 234 includes a diffuser 250 having a wall 266, a first plurality of vanes 270 that extend from the wall 266, and a second plurality of vanes 272 that extend from the wall 266. The wall 266 includes a first portion 330 that extends in a first direction from the disc 262 and toward the fan 238 to surround the outer periphery 298 of the fan 238, forming a first edge 263, and a second portion 334 that extends away from the first portion 330 in a second direction from the disc 262 and toward the motor 242 along the output shaft of the motor 242 and away from the fan 238, forming a second edge 264. The first plurality of vanes 270 extend radially outward from the first portion 330 and the outer surface 294 of the wall 266. The first plurality of vanes 270 are positioned between the disc 262 and the first edge 263 of the first portion 330 of the wall 266. The second plurality of vanes 272 extend radially outward from the second portion 334 and the outer surface 294 of the wall 266. The second plurality of vanes 272 are positioned between the disc 262 and the second edge 264 of the second portion 334 of the wall 266. The first plurality of vanes 270 and the second plurality of vanes 272 both include airfoil-shaped vanes.
The motor-fan assembly 434 includes the diffuser 450 having a wall 466 and a plurality of vanes 470. The wall 466 extends in a direction from the disc 462 and toward the motor 442 along the output shaft of the motor 442 and away from the fan 438, forming a first edge 463 and a second edge 264. The plurality of vanes 470 are coupled to an outer surface 494 of the wall 466 and extend radially outward from the outer surface 494 of the wall 466. The plurality of vanes 470 are positioned between the first edge 463 and the second edge 464 of the wall 466 such that the vanes 470 do not extend past the edges 463 and 464.
The motor-fan assembly 634 includes the diffuser 650 having an inner wall 666, a plurality of vanes 670, and an outer wall 668. The inner wall 666 surrounds an outer periphery 686 of a disc 662 and includes an inner surface 730 that faces toward the output shaft of the motor 642 and an outer surface 734 that faces away from the inner surface 730. The inner wall 666 extends in a direction from the disc 662 and toward the fan 638 to surround the outer periphery 698 of the fan 638, forming a first edge 663 and a second edge 664. The plurality of vanes 670 are coupled to the outer surface 734 of the inner wall 666 and extend radially outward from the outer surface 734 of the inner wall 666. The plurality of vanes 670 are positioned between the first edge 663 and the second edge 664 of the inner wall 666. The outer wall 668 is located radially outward from the inner wall 666, away from the output shaft of the motor 642 such that the plurality of vanes 670 extend between the inner wall 666 and the outer wall 668.
Various features and advantages of the invention are set forth in the following claims.