US20070025848A1 - Reduced noise diffuser for a motor-fan assembly - Google Patents
Reduced noise diffuser for a motor-fan assembly Download PDFInfo
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- US20070025848A1 US20070025848A1 US11/193,908 US19390805A US2007025848A1 US 20070025848 A1 US20070025848 A1 US 20070025848A1 US 19390805 A US19390805 A US 19390805A US 2007025848 A1 US2007025848 A1 US 2007025848A1
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- motor
- diffuser
- fan
- vanes
- vane
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- 230000000712 assembly Effects 0.000 description 18
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- 230000001070 adhesive effect Effects 0.000 description 1
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- 230000001010 compromised effect Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
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- 239000013589 supplement Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/40—Casings; Connections of working fluid
- F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
- F04D29/44—Fluid-guiding means, e.g. diffusers
- F04D29/441—Fluid-guiding means, e.g. diffusers especially adapted for elastic fluid pumps
- F04D29/444—Bladed diffusers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2250/00—Geometry
- F05D2250/50—Inlet or outlet
- F05D2250/52—Outlet
Definitions
- the present invention generally relates to diffusers used in association with various motor-fan systems. More particularly, the present invention relates to an air diffuser that reduces vane passage frequencies, and associated noise, which is generated from air movement over the surface of the diffuser. Specifically, the present invention is directed to a noise reducing diffuser that operatively secures the brushes of an electric motor. More specifically, the present invention relates to a noise reducing diffuser that is interchangeable with existing diffusers installed in various motor-fan units.
- Electric motors are well known in the art and have been put to use in a variety of applications, including the handling of air.
- an electric motor is coupled to a fan, creating a motor-fan unit, which produces an airflow as needed.
- the motor-fan unit may supply cooling air to the motor, so as to maintain the motor's operating temperature at an optimal level, allowing the motor's operating life to be extended.
- the motor-fan unit may also be used to generate working air for vacuum type devices.
- the fan is mounted on a motor driven shaft, which draws air into a fan shroud.
- the fan shroud compresses or pressurizes the incoming air, which is resultantly released into the motor housing via one or more ports in a diffuser plate, causing the air to be directed toward the motor windings.
- the heat from the motor is drawn into the airflow and exhausted from the motor housing, thus enhancing the motor's operating life.
- the motor itself comprises field windings that surround an armature that is centrally located on a shaft, which is rotatably mounted on suitable bearings.
- a commutator is also mounted on the shaft and placed in electrical contact with a power supply by a pair of opposed brushes contacting the commutator.
- these brushes and/or armature are completely or partially closed off from the cooling air provided by the fan unit. As such, the motor's efficiency and operating life are reduced due to the heat generated by the motor.
- a diffuser for a motor-fan unit with radial turning vanes that has an integrated baffle plate to provide reduced noise during the motor-fan unit's operation. Additionally, there is a need for a reduced noise diffuser that allows cooling air to pass to the brushes and/or armature of the motor while supporting the brushes of the motor. Further, there is a need for an interchangeable diffuser with reduced vane passage frequencies, and reduced noise generation that can be used in association with existing motor-fan assemblies, while providing suitable cooling for the motor's armature and/or brushes.
- It is yet another aspect of the present invention to provide a motor-fan assembly comprising a field winding; an armature having a shaft, the armature rotatably mounted within the field winding; a fan attached to the shaft; and a diffuser interposed between the fan and the field winding, the diffuser comprising a baffle plate having a motor side and a fan side; the baffle plate having an opening therethrough; a plurality of vanes extending from the motor side; each vane having an external portion which radially extends from the baffle plate wherein adjacent vanes have a port therebetween; and the plurality of vanes directing airflow generated by the fan from the fan side through the ports to the motor side.
- FIG. 1 is a partially sectioned front elevational view of a motor-fan unit according to the present invention showing the details of a motor assembly, an end plate assembly, a diffuser assembly, and a fan assembly;
- FIG. 2 is an exploded perspective top view of the motor-fan unit according to the present invention depicting details of the motor assembly, the end plate assembly, the diffuser assembly, and the fan assembly;
- FIG. 3 is an exploded perspective bottom view of the motor-fan unit according to the present invention depicting details of the motor assembly, the end plate assembly, the diffuser assembly, and the fan assembly;
- FIG. 4 is a plan view of the end plate assembly depicting details of a motor-side of the end plate;
- FIG. 5 is an elevational view of the end plate assembly depicting further details of the end plate assembly, including a brush retainer assembly and motor brackets;
- FIG. 6 is a partially sectioned side elevational view of the end plate assembly depicting details of a commutator receiver
- FIG. 7 is a perspective view of the end plate assembly depicting further details of the motor-side thereof, including the location of brush retainers adjacent the commutator receiver;
- FIG. 8 is an enlarged partially sectioned side elevational view as seen along line 8 - 8 in FIG. 4 , depicting details of the brush retainer according to the present invention
- FIG. 9 is a plan view of the end plate according to the present invention depicting details of the diffuser side of the end plate assembly
- FIG. 10 is a perspective view of a fan side of the diffuser assembly according to the present invention.
- FIG. 11 is a plan view of the diffuser assembly including a baffle plate, a plurality of external vanes, and a plurality of diffuser ports;
- FIG. 12 is a perspective view of a motor side of the diffuser assembly according to the present invention.
- FIG. 13 is a perspective view of a diffuser assembly according to the present invention depicting brush cap assemblies extending from the surface of the diffuser assembly;
- FIG. 14 is a plan view of a diffuser assembly according to the present invention showing the pair of brush cap assemblies located adjacent a central opening of the diffuser;
- FIG. 15 is a front sectional view along line 15 - 15 in FIG. 14 of the diffuser assembly according to the present invention depicting the brush cap assemblies extending axially inward to protrude beyond the radial channel members located on the diffuser;
- FIG. 16 is a side sectional view along line 16 - 16 in FIG. 14 of the diffuser assembly according to the present invention depicting details of the brush cap assemblies, including a channel formed within each cap assembly to direct air toward the brushes in the motor-fan unit;
- FIG. 17 is a perspective view of the diffuser according to the present invention enlarged to show details of an alternative brush cap assembly having snap-lock projections located thereon to effect attachment of the end cap assembly to the diffuser assembly;
- FIG. 18 is an enlarged perspective view of an end plate and diffuser according to the present invention having an alternative brush cap assemblies with snap lock projections that engage surfaces on the commutator receiver of the end plate to couple the end plate to the diffuser.
- a motor-fan unit indicated generally by the numeral 10 in the accompanying FIGS. 1-3 , generally includes a motor assembly 12 and a fan assembly 14 .
- the motor assembly 12 comprises a lamination stack 16 , an armature 18 , field windings 19 , a commutator 20 , and brushes 22 (best seen in FIG. 7 ).
- a shaft 24 with a mounted armature 18 is supported by suitable bearings 26 , such that the shaft 24 rotates when the motor assembly is energized.
- the commutator 20 allows the shaft 24 to rotate while allowing the armature 18 to remain electrically connected with a power supply (not shown) via the brushes 22 .
- the motor assembly 12 is configured with the commutator 20 proximate the fan assembly 14 .
- the fan assembly 14 of the motor-fan unit 10 comprises a fan 28 coupled to an end 30 of the shaft 24 that is proximate the commutator 20 , via a nut 32 .
- any other type of suitable system for connecting the fan 28 to the shaft 24 may be utilized.
- Covering the outside of the fan assembly 14 is a shroud 34 .
- the shroud 34 has a cover portion 38 which has a centrally positioned intake port 36 that is coaxially located with axis A of shaft 24 .
- the intake port 36 allows the fan assembly 14 to draw air into the shroud 34 where it is pressurized or compressed and radially exhausted. The air may then be directed through the motor assembly.
- the motor assembly 12 is provided with an end plate assembly which is generally indicated by the numeral 42 shown in FIGS. 1-9 .
- the end plate assembly 42 shown clearly in FIGS. 2 and 3 , generally includes a planar plate portion 44 , which may be annular as shown, and a motor bracket portion 46 that extends from the plate portion 44 toward the motor 16 .
- the motor bracket portion 46 shown more clearly in FIGS. 4 and 5 , is adapted to allow the motor assembly 12 to be rigidly mounted or fixated to the end plate assembly 42 .
- the end plate assembly 42 defines a central opening 47 , which receives the end of the motor's shaft 24 that is proximate the commutator 20 .
- the end plate assembly 42 may be provided with a commutator receiver, generally indicated by the numeral 48 that receives the commutator 20 and provides suitable clearance for the free rotation of the commutator 20 .
- the commutator receiver 48 shown clearly in FIGS. 5 and 6 may bulge axially outwardly of planar plate portion 44 to define a well 50 , in which at least a portion of the commutator 20 resides.
- the well 50 may also retain a bearing 26 which is used to support the shaft 24 , thereby allowing the shaft 24 to freely rotate.
- the commutator receiver 48 may include a plurality of stepped concentric recesses 52 , 54 , 56 that accommodate the profile of both the commutator 20 and the bearing 26 .
- a fastening plate 58 is used in order to secure the motor assembly 12 to the end plate 42 .
- the fastening plate 58 has tabs 60 with holes therethrough for receiving fasteners that are secured into a receiver 61 carried by each motor bracket portion 46 .
- each brush retainer 62 is largely identical to the other, with one brush retainer 62 being a mirror image of the other. Therefore, the following discussion will describe only a single brush retainer 62 . As shown in FIGS. 4-8 , and more clearly seen in FIGS.
- the brush retainer 62 may be in the form of a channel-like member having three contiguous walls or members 64 , 66 , and 68 that define an open end 70 , such that the three contiguous walls or members 64 , 66 , 68 serve to cradle the brush 22 . It is also contemplated that the brush retainer 62 protrudes toward the motor assembly 12 to facilitate the manufacture thereof.
- the brush retainers 62 each contain an open mouth 72 , which is contiguous with the open end 70 , and which opens toward the fan assembly 14 .
- a projection in a mold cavity may be used to create the open mouth 72 of the brush retainer 62 during fabrication.
- mold design is greatly simplified, and the use of sacrificial molding or subsequent machining to create tubular brush retainers as used in the art is obviated.
- the formation of an open, resilient-type brush retainer 62 allows for interference fitting of the brush 22 within the brush retainer 62 . As a result of this interference fit, the use of retaining clips, which are commonly used when attaching the brush 22 to a motor housing, are eliminated.
- the brush retainer 62 may be formed as a single piece or may contain spaced portions to suitably support the brush 22 .
- the brush retainer 62 may include an L-shaped member or may incorporate one or more posts to locate the position of the brush 22 .
- the brush retainer 62 includes a wall or member 64 that extends axially outward from the plate portion 44 toward the motor assembly 12 , a wall or member 66 that extends outwardly from and generally at a right angle to the wall or member 64 , and a wall or member 68 extending axially toward the plate portion 44 from the wall or member 66 .
- the wall or member 66 is axially spaced from the end plate 42 to define a suitable vertical clearance 74 for the brush 22
- the wall or members 68 and 64 serve to define a horizontal clearance 76 .
- the wall or members 64 , 66 , and 68 may be spaced such that clearances 74 and 76 create an interference fit between the brush 22 and the brush retainer 62 . It should also be appreciated that the wall or member 68 may not make a complete connection with the plate portion 44 . Thus, a gap or notch 78 is created between the plate portion 44 and the wall or member 68 along one side of the brush retainer 62 , as shown.
- a support member 80 such as a post, may extend axially from the plate portion 36 to support the cantilevered members 66 and 68 . The support member 80 is placed adjacent the brush retainer 62 near an edge 82 of the brush retainer 62 that is closest to the commutator receiver 48 . At this location, the support member 80 may further aid the brush retainer 62 in maintaining the position of the brush 22 .
- the brush 22 is biased into engagement with the commutator 20 , as shown in FIG. 7 .
- the biasing action is performed by a spring 84 mounted on a spring holder 86 that is provided by the end plate assembly 42 .
- a spring is typically used, other systems for biasing the brushes are contemplated.
- the spring 84 includes a coil 88 , a leg 90 , and a leg 92 which are employed to bias the brush 22 toward the commutator 20 .
- the coil 88 is press fit over the spring holder 86 , and the leg 90 is fixed in place with a suitable clip, such as spring retainer projection 94 that is formed on the plate portion 44 .
- spring retainer projection 94 may comprise a wall
- an L-shaped projection may be used as shown in FIG. 7 .
- the torsional force generated by the spring 84 holds leg 90 against spring retaining projection 94 , thus preventing leg 90 from moving axially beyond spring retaining projection 94 .
- Leg 92 of the spring 84 is positioned so that it contacts the rear of the brush 22 , and causes the brush 22 to be urged toward the commutator 20 . Since the brush 22 may be inserted after the assembly of the motor assembly 12 , it may be necessary to preload the spring 84 to temporarily hold it in place.
- a spring retaining projection 96 may be provided on the surface of the end plate assembly 42 or the brush retainer 62 .
- the spring retaining projection 96 is located so that when the leg 92 of the spring 84 is compressed, a torsional force is created within the spring 60 sufficient to hold leg 92 against the spring retaining projection 96 .
- an L-shaped spring retaining projection 96 extends axially inward from member 66 of the brush retainer 62 , thereby defining a spring recess 98 in which an end 100 of leg 92 may be inserted to allow the spring 84 to assume a preloaded condition as shown in FIG. 4 .
- leg 92 Prior to placing the brush 22 within the brush retainer 62 , leg 92 is compressed so that it clears the brush retainer 62 and any extending portion of the brush 22 . Once the brush is inserted within the brush retainer 62 , the leg 92 is placed in contact with the rear of brush 22 to urge the brush 22 toward the commutator 20 .
- the brush retainers 62 define an open mouth 72 within the end plate assembly 42 , which open toward the fan assembly 14 and extend into a portion of the commutator receiver 48 .
- the opening of the mouth 72 allows cooling air from the fan assembly 14 to flow past the brushes 22 , and motor 16 as will be described more completely below.
- the end plate assembly 42 provides a pair of cavities 104 . These cavities 104 may be at least partially sealed from the mouth 72 , to prevent particulates generated from the brushes 22 from being carried downstream into the other areas of the motor assembly 12 .
- dividers 106 and 108 extend from the plate assembly 42 .
- a bead of sealant may be provided, which extends adjacent cavities 104 , and between the cavities 104 and each mouth 72 of the brush retainer 62 .
- the dividers 106 , 108 generally cordon off a sector surrounding each of the mouths 72 , such that the plate portion 44 is separated into distinct regions.
- Air drawn into the shroud 34 by the fan assembly 14 is directed to the motor 16 by a diffuser assembly that is designated generally by the numeral 120 .
- the diffuser assembly 120 is interposed between the fan 28 and the end plate assembly 42 and is configured to be interchangeable with existing diffuser assemblies that are part of other motor-fan units 10 . That is, the diffuser assembly 120 of the present invention is designed to cooperate with end plate assemblies 42 of varying motor-fan units 10 so that the brushes 22 of such unit 10 are sufficiently supported.
- the diffuser assembly 120 includes a baffle plate 122 which provides a fan side 123 which is opposite a motor side 124 . The fan side 123 is positioned adjacent the fan assembly 14 when the motor-fan unit 10 is assembled.
- the motor side 124 is positioned adjacent the end plate assembly 42 and the motor assembly 12 when the unit 10 is assembled.
- the baffle plate 122 includes an outer edge 125 which joins the fan side 123 to the motor side 124 and the plate also provides a central opening 126 extending therethrough.
- the central opening 126 receives and seats the commutator receiver 48 to allow contact between the commutator 20 and the brushes 22 .
- Extending from the motor side 124 are a plurality of curvilinear vanes designated generally by the numeral 128 .
- the vanes 128 are spaced apart and each vane has a plate edge 129 connected to the motor side and a ring edge 130 opposite the plate edge.
- the curvilinear vanes 128 are disposed about the outer periphery of the motor side 124 .
- each vane 128 provides an external portion 131 that extends radially outwardly from the outer edge 125 on the motor side 124 and an internal portion 132 that extends from the motor side 124 .
- the adjacent vanes 124 form a port 134 therebetween.
- a vane support ring 135 connects the external portions of the curvilinear vanes to one another and, in particular, joins the respective ring edges 130 of each vane 128 .
- the ring 135 has an inner diameter edge 136 and an outer diameter edge 137 . It will be appreciated that the inner edge 136 has a diameter equal to or somewhat greater than the diameter of the outer edge 125 .
- the internal portions 132 of the curvilinear vanes 128 collectively form a collection chamber designated generally by the numeral 138 .
- the construction of the baffle plate 122 is ideally suited for a molded construction, but it will be appreciated that other materials could be used in formation thereof. Accordingly, the curvilinear vanes 128 are integral with the baffle plate 122 and the vane support ring 135 to provide a sturdy and easily manufactured construction.
- the curvilinear vanes 128 may comprise radial turning vanes, wherein the number of vanes is equal to that of a prime number. It is believed that by having such an arrangement, the diffuser assembly 120 is able to reduce the harmonic interaction between the fan 14 and the diffuser at certain revolutions-per-minute multiples as the fan assembly 14 rotates. In general, many harmonics may be generated by air passing by over the surface of the diffuser vanes. For example, in arrangements where a diffuser utilizes a number of vanes not equal to a prime number, generated harmonics may occur at multiples of the smallest mathematical factor for the number of vanes present. In contrast, a diffuser having a number of vanes equal to that of a prime number only has two factors (i.e.
- the use of the diffuser 128 with a number of vanes equal to that of a prime number eliminates the factor harmonics that would otherwise be created by a diffuser with a number of vanes not equal to a prime number.
- the vanes 128 may comprise radial turning vanes and/or may be equal in number to that of a prime number.
- the number of turning vanes 128 may total 23, 29, or 37, although any other suitable prime number of turning vanes 128 may be utilized.
- the diffuser assembly 120 is able to reduce the harmonic interaction between the fan 14 and the diffuser 120 at certain rpm multiples as the motor-fan unit 10 is in operation. More specifically, as high velocity air departs from a vane the resulting airflow also includes a vortex component that shears against other nearby vanes resulting in noise.
- the generated noise has its largest magnitude at frequencies equal to the multiples of the fan revolutions per minute (rpm) and the number of diffuser vanes.
- the noise frequencies with higher magnitudes may be shifted to different frequencies, thus minimizing the noise that would otherwise occur. As such, the noise generated by air passing through the diffuser 120 is thereby reduced.
- the diffuser assembly 120 contains one or more brush cap assemblies 139 .
- the brush cap assemblies 139 may be made integral with the baffle plate 122 during manufacturing of the diffuser 120 , or may be connected to the baffle plate 122 using known techniques, including but not limited to thermal welding, adhesives, or screw-type connection.
- the brush cap assemblies 139 are configured to coact with the brush retainer 62 to trap the brushes 22 therebetween.
- the brush cap assemblies 139 provide a surface that substantially closes the open mouth 72 of the brush retainer 62 located on the end plate assembly 42 .
- the brush caps 139 may extend axially toward the motor assembly 12 , beyond the vanes 128 to a desired extent. In one arrangement, the brush cap assembly 139 will not extend such that its contact with the brushes 22 would interfere with the proper assembly of the motor-fan unit 10 .
- the brush cap assembly 139 generally conforms to the contours of the mouth 72 of the brush retainer 62 , and may be toleranced to provide a clearance that would allow dust or particulates from the brushes 22 to escape through open end 70 of the brush retainers 62 .
- the brush cap assemblies 139 have a generally rectangular shape to conform to the rectangular opening of the open mouths 72 of the end plate assembly 42 .
- the brush cap assemblies 139 may be provided with channels 140 .
- the channels 140 are formed between upstanding members 142 and 144 that are positioned on the motor side 124 of the diffuser 120 .
- Members 142 , 144 are generally located adjacent the diffuser central opening 126 and may radially project to an extent into the opening.
- recess window 146 may be formed on the commutator receiver 48 , as shown clearly in FIG. 7 .
- an interference or friction fit between the members 142 , 144 and the commutator receiver 48 may be used in coupling the end plate assembly 42 and the diffuser assembly 120 together.
- Upstanding members 142 and 144 are of a suitable height to the internal curvilinear vanes 128 to allow for proper attachment of the diffuser assembly 120 to the end plate assembly 42 . Further, upstanding members 142 , 144 may extend sufficiently beyond the height of the vanes 128 to an extent, such that they extend into the open mouths 72 defined by brush retainers 62 . As a result the diffuser 120 is capable of attachment to the end plate assembly 42 . Upstanding member 142 may have a raised edge 148 sized to fill the gap or notch 78 between the plate portion 44 and member 68 of the brush retainer 62 . In this way, the brush cap assembly 139 encloses the brushes 22 when the end plate 42 and diffuser 120 are coupled to one another.
- upstanding member 142 Adjacent the raised edge 148 , upstanding member 142 may be provided with a landing 150 , which has the same height as upstanding member 144 , thereby forming a recessed area that lies adjacent to the brush 22 when the diffuser assembly 120 and end plate assembly 42 are joined.
- the channel 140 opens toward the motor assembly 12 between the landing 150 and upstanding member 144 . This arrangement, allows air generated by the fan assembly 14 to be distributed across the exposed surface 152 of the brush 22 that lies adjacent the brush cap assemblies 139 shown in FIG. 7 . The air directed through the channels 140 allows heat from the brushes 22 to be carried away, thus improving operation of the motor 16 .
- FIGS. 17 and 18 An alternative embodiment of the brush cap assemblies 139 are shown in FIGS. 17 and 18 , which may be used in coupling the diffuser 120 to the end plate assembly 42 .
- the brush cap assembly 139 may be provided with a projecting surface, generally indicated by the numeral 154 , that performs a snap-lock function in connection with an attachment surface 156 provided by the recess window 146 of the end plate assembly 42 .
- projecting surface 154 may be one of a number of configurations commonly used in the art to perform a snap-lock function, including but not limited to a flexible tab, a rounded surface, or a tapered leading surface 158 and stop surface 160 combination as shown in FIG. 17 .
- brush cap assemblies 139 may have triangular projections 162 extending radially inward from each member 142 , 144 .
- the tapered surface 158 of projection 162 slopes outwardly from a member 142 or 144 toward diffuser 80 .
- a stop surface 160 extends inwardly from the tapered surface 158 and is located vertically on members 142 , 144 to provide a clearance at 164 for the receipt of a portion of the commutator receiver 40 .
- the tapered surface 158 causes gradual deflection of members 142 , 144 and/or the members 64 , 66 , 68 of the commutator receiver 40 .
- one advantage of one or more embodiments of the present invention is that the noise and vane passage frequencies associated with air movement over the diffuser's vanes are reduced. Still another advantage of the present invention is that the diffuser plate is configured, such that, the diffuser is capable of replacing a previously installed diffuser of an existing motor-fan unit. Yet another advantages of the present invention is that the diffuser is able to support the brushes of the motor-fan unit without additional adjustment to the diffuser.
Abstract
An air diffuser for a motor-fan unit having reduced blade passage frequencies, and reduced noise generation, includes a baffle plate, external vanes, internal vanes, diffuser ports, and a central opening. The baffle plate of the diffuser is made integral with the internal and external vanes, such that any leaking, rattling, or pure tone noise that may be generated from air movement over the surface of the diffuser are prevented or reduced. Additionally, the number of internal and external vanes provided by the diffuser is that equal to a prime number, thus resulting in a reduction of harmonic and pure tone noise generated during the operation of the motor-fan unit.
Description
- The present invention generally relates to diffusers used in association with various motor-fan systems. More particularly, the present invention relates to an air diffuser that reduces vane passage frequencies, and associated noise, which is generated from air movement over the surface of the diffuser. Specifically, the present invention is directed to a noise reducing diffuser that operatively secures the brushes of an electric motor. More specifically, the present invention relates to a noise reducing diffuser that is interchangeable with existing diffusers installed in various motor-fan units.
- Electric motors are well known in the art and have been put to use in a variety of applications, including the handling of air. In this circumstance, an electric motor is coupled to a fan, creating a motor-fan unit, which produces an airflow as needed. When providing air movement, the motor-fan unit may supply cooling air to the motor, so as to maintain the motor's operating temperature at an optimal level, allowing the motor's operating life to be extended. The motor-fan unit may also be used to generate working air for vacuum type devices.
- To achieve this effect, the fan is mounted on a motor driven shaft, which draws air into a fan shroud. The fan shroud compresses or pressurizes the incoming air, which is resultantly released into the motor housing via one or more ports in a diffuser plate, causing the air to be directed toward the motor windings. As a result, the heat from the motor is drawn into the airflow and exhausted from the motor housing, thus enhancing the motor's operating life.
- Many diffusers used with motor-fan units, incorporate radial turning vanes with a separately attached baffle plate to move the pressurized air from the fan shroud to the motor assembly. However, the baffle plates of these diffusers are not made integral with the turning vanes. This results in a baffle plate that does not form a complete seal with the attached turning vanes. Because of this inadequate or compromised seal, the diffuser generates leaking, rattling, and pure tone noises as the motor-fan unit draws air through the diffuser. In addition, blade passage frequencies are also created as air is passed over the diffuser's vanes. As such, many motor-fan units are uncomfortably noisy to many users. Further, the use of such motor-fan units may be limited to those applications where such noise can be tolerated.
- In addition to the diffuser portion of the motor-fan unit, the motor itself comprises field windings that surround an armature that is centrally located on a shaft, which is rotatably mounted on suitable bearings. A commutator is also mounted on the shaft and placed in electrical contact with a power supply by a pair of opposed brushes contacting the commutator. Typically, these brushes and/or armature are completely or partially closed off from the cooling air provided by the fan unit. As such, the motor's efficiency and operating life are reduced due to the heat generated by the motor.
- Therefore, there is a need for a diffuser for a motor-fan unit with radial turning vanes that has an integrated baffle plate to provide reduced noise during the motor-fan unit's operation. Additionally, there is a need for a reduced noise diffuser that allows cooling air to pass to the brushes and/or armature of the motor while supporting the brushes of the motor. Further, there is a need for an interchangeable diffuser with reduced vane passage frequencies, and reduced noise generation that can be used in association with existing motor-fan assemblies, while providing suitable cooling for the motor's armature and/or brushes.
- In light of the foregoing, it is a first aspect of the present invention to provide a reduced noise diffuser for a motor-fan assembly.
- It is another aspect of the present invention to provide a diffuser interposed between a shrouded fan assembly and a motor assembly having a shaft that rotates a fan carried within the shrouded fan assembly, the diffuser comprising a baffle plate having a motor side and a fan side, the baffle plate having an opening therethrough; and a plurality of vanes extending from the motor side, each vane having an external portion which radially extends from the baffle plate, wherein adjacent vanes have a port therebetween, the plurality of vanes directing air flow generated by the fan from the fan side through the ports to the motor side.
- It is yet another aspect of the present invention to provide a motor-fan assembly comprising a field winding; an armature having a shaft, the armature rotatably mounted within the field winding; a fan attached to the shaft; and a diffuser interposed between the fan and the field winding, the diffuser comprising a baffle plate having a motor side and a fan side; the baffle plate having an opening therethrough; a plurality of vanes extending from the motor side; each vane having an external portion which radially extends from the baffle plate wherein adjacent vanes have a port therebetween; and the plurality of vanes directing airflow generated by the fan from the fan side through the ports to the motor side.
- These and other features and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
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FIG. 1 is a partially sectioned front elevational view of a motor-fan unit according to the present invention showing the details of a motor assembly, an end plate assembly, a diffuser assembly, and a fan assembly; -
FIG. 2 is an exploded perspective top view of the motor-fan unit according to the present invention depicting details of the motor assembly, the end plate assembly, the diffuser assembly, and the fan assembly; -
FIG. 3 is an exploded perspective bottom view of the motor-fan unit according to the present invention depicting details of the motor assembly, the end plate assembly, the diffuser assembly, and the fan assembly; -
FIG. 4 is a plan view of the end plate assembly depicting details of a motor-side of the end plate; -
FIG. 5 is an elevational view of the end plate assembly depicting further details of the end plate assembly, including a brush retainer assembly and motor brackets; -
FIG. 6 is a partially sectioned side elevational view of the end plate assembly depicting details of a commutator receiver; -
FIG. 7 is a perspective view of the end plate assembly depicting further details of the motor-side thereof, including the location of brush retainers adjacent the commutator receiver; -
FIG. 8 is an enlarged partially sectioned side elevational view as seen along line 8-8 inFIG. 4 , depicting details of the brush retainer according to the present invention; -
FIG. 9 is a plan view of the end plate according to the present invention depicting details of the diffuser side of the end plate assembly; -
FIG. 10 is a perspective view of a fan side of the diffuser assembly according to the present invention; -
FIG. 11 is a plan view of the diffuser assembly including a baffle plate, a plurality of external vanes, and a plurality of diffuser ports; -
FIG. 12 is a perspective view of a motor side of the diffuser assembly according to the present invention; -
FIG. 13 is a perspective view of a diffuser assembly according to the present invention depicting brush cap assemblies extending from the surface of the diffuser assembly; -
FIG. 14 is a plan view of a diffuser assembly according to the present invention showing the pair of brush cap assemblies located adjacent a central opening of the diffuser; -
FIG. 15 is a front sectional view along line 15-15 inFIG. 14 of the diffuser assembly according to the present invention depicting the brush cap assemblies extending axially inward to protrude beyond the radial channel members located on the diffuser; -
FIG. 16 is a side sectional view along line 16-16 inFIG. 14 of the diffuser assembly according to the present invention depicting details of the brush cap assemblies, including a channel formed within each cap assembly to direct air toward the brushes in the motor-fan unit; -
FIG. 17 is a perspective view of the diffuser according to the present invention enlarged to show details of an alternative brush cap assembly having snap-lock projections located thereon to effect attachment of the end cap assembly to the diffuser assembly; and -
FIG. 18 is an enlarged perspective view of an end plate and diffuser according to the present invention having an alternative brush cap assemblies with snap lock projections that engage surfaces on the commutator receiver of the end plate to couple the end plate to the diffuser. - A motor-fan unit, indicated generally by the
numeral 10 in the accompanyingFIGS. 1-3 , generally includes amotor assembly 12 and afan assembly 14. Themotor assembly 12 comprises alamination stack 16, anarmature 18,field windings 19, acommutator 20, and brushes 22 (best seen inFIG. 7 ). Ashaft 24 with a mountedarmature 18 is supported bysuitable bearings 26, such that theshaft 24 rotates when the motor assembly is energized. Thecommutator 20 allows theshaft 24 to rotate while allowing thearmature 18 to remain electrically connected with a power supply (not shown) via thebrushes 22. - As shown in
FIG. 1 , themotor assembly 12 is configured with thecommutator 20 proximate thefan assembly 14. Thefan assembly 14 of the motor-fan unit 10, comprises afan 28 coupled to anend 30 of theshaft 24 that is proximate thecommutator 20, via anut 32. However, any other type of suitable system for connecting thefan 28 to theshaft 24 may be utilized. Covering the outside of thefan assembly 14 is ashroud 34. Theshroud 34 has acover portion 38 which has a centrally positionedintake port 36 that is coaxially located with axis A ofshaft 24. Theintake port 36 allows thefan assembly 14 to draw air into theshroud 34 where it is pressurized or compressed and radially exhausted. The air may then be directed through the motor assembly. - The
motor assembly 12 is provided with an end plate assembly which is generally indicated by thenumeral 42 shown inFIGS. 1-9 . Theend plate assembly 42, shown clearly inFIGS. 2 and 3 , generally includes aplanar plate portion 44, which may be annular as shown, and amotor bracket portion 46 that extends from theplate portion 44 toward themotor 16. Themotor bracket portion 46, shown more clearly inFIGS. 4 and 5 , is adapted to allow themotor assembly 12 to be rigidly mounted or fixated to theend plate assembly 42. Continuing withFIGS. 3 and 4 , theend plate assembly 42 defines acentral opening 47, which receives the end of the motor'sshaft 24 that is proximate thecommutator 20. Theend plate assembly 42 may be provided with a commutator receiver, generally indicated by the numeral 48 that receives thecommutator 20 and provides suitable clearance for the free rotation of thecommutator 20. Thecommutator receiver 48 shown clearly inFIGS. 5 and 6 may bulge axially outwardly ofplanar plate portion 44 to define a well 50, in which at least a portion of thecommutator 20 resides. The well 50 may also retain abearing 26 which is used to support theshaft 24, thereby allowing theshaft 24 to freely rotate. In addition, thecommutator receiver 48 may include a plurality of steppedconcentric recesses commutator 20 and thebearing 26. This arrangement allows thecommutator 20 to be placed close to thefan assembly 14, such that thecommutator 20 can receive cooling air prior to the air's passage over the motor'sarmature 18. As a result, thecommutator 20 is more efficiently cooled, and the performance of the motor is enhanced. Returning toFIGS. 2 and 3 , it is shown that in order to secure themotor assembly 12 to theend plate 42, afastening plate 58 is used. Thefastening plate 58 hastabs 60 with holes therethrough for receiving fasteners that are secured into areceiver 61 carried by eachmotor bracket portion 46. - Because the
brushes 22 make electrical contact with thecommutator 20 during the operation of the motor-fan unit 10, a pair of brush retainers generally indicated by the 5numeral 62 are provided by theend plate assembly 42. The structure of eachbrush retainer 62 is largely identical to the other, with onebrush retainer 62 being a mirror image of the other. Therefore, the following discussion will describe only asingle brush retainer 62. As shown inFIGS. 4-8 , and more clearly seen inFIGS. 6-8 , thebrush retainer 62 may be in the form of a channel-like member having three contiguous walls ormembers open end 70, such that the three contiguous walls ormembers brush 22. It is also contemplated that thebrush retainer 62 protrudes toward themotor assembly 12 to facilitate the manufacture thereof. - As shown in
FIG. 9 , thebrush retainers 62 each contain anopen mouth 72, which is contiguous with theopen end 70, and which opens toward thefan assembly 14. A projection in a mold cavity may be used to create theopen mouth 72 of thebrush retainer 62 during fabrication. Thus, by using theopen mouth 72, mold design is greatly simplified, and the use of sacrificial molding or subsequent machining to create tubular brush retainers as used in the art is obviated. Further, the formation of an open, resilient-type brush retainer 62 allows for interference fitting of thebrush 22 within thebrush retainer 62. As a result of this interference fit, the use of retaining clips, which are commonly used when attaching thebrush 22 to a motor housing, are eliminated. Thebrush retainer 62, may be formed as a single piece or may contain spaced portions to suitably support thebrush 22. As an alternative to the channel-like brush retainer 62 shown in the Figs., it is also contemplated that thebrush retainer 62 may include an L-shaped member or may incorporate one or more posts to locate the position of thebrush 22. - Continuing with the
brush retainer 62 as shown inFIGS. 7 and 8 , thebrush retainer 62 includes a wall ormember 64 that extends axially outward from theplate portion 44 toward themotor assembly 12, a wall ormember 66 that extends outwardly from and generally at a right angle to the wall ormember 64, and a wall ormember 68 extending axially toward theplate portion 44 from the wall ormember 66. The wall ormember 66 is axially spaced from theend plate 42 to define a suitablevertical clearance 74 for thebrush 22, while the wall ormembers horizontal clearance 76. As previously discussed, the wall ormembers clearances brush 22 and thebrush retainer 62. It should also be appreciated that the wall ormember 68 may not make a complete connection with theplate portion 44. Thus, a gap or notch 78 is created between theplate portion 44 and the wall ormember 68 along one side of thebrush retainer 62, as shown. Asupport member 80, such as a post, may extend axially from theplate portion 36 to support the cantileveredmembers support member 80 is placed adjacent thebrush retainer 62 near anedge 82 of thebrush retainer 62 that is closest to thecommutator receiver 48. At this location, thesupport member 80 may further aid thebrush retainer 62 in maintaining the position of thebrush 22. - To ensure contact between the
brush 22 and thecommutator 20 of themotor 16, thebrush 22 is biased into engagement with thecommutator 20, as shown inFIG. 7 . The biasing action is performed by aspring 84 mounted on aspring holder 86 that is provided by theend plate assembly 42. Although a spring is typically used, other systems for biasing the brushes are contemplated. Specifically, thespring 84 includes acoil 88, aleg 90, and aleg 92 which are employed to bias thebrush 22 toward thecommutator 20. Thecoil 88 is press fit over thespring holder 86, and theleg 90 is fixed in place with a suitable clip, such asspring retainer projection 94 that is formed on theplate portion 44. - While
spring retainer projection 94 may comprise a wall, an L-shaped projection may be used as shown inFIG. 7 . Thus, the torsional force generated by thespring 84 holdsleg 90 againstspring retaining projection 94, thus preventingleg 90 from moving axially beyondspring retaining projection 94.Leg 92 of thespring 84 is positioned so that it contacts the rear of thebrush 22, and causes thebrush 22 to be urged toward thecommutator 20. Since thebrush 22 may be inserted after the assembly of themotor assembly 12, it may be necessary to preload thespring 84 to temporarily hold it in place. To assist in the preloading of thespring 84, aspring retaining projection 96 may be provided on the surface of theend plate assembly 42 or thebrush retainer 62. Thespring retaining projection 96 is located so that when theleg 92 of thespring 84 is compressed, a torsional force is created within thespring 60 sufficient to holdleg 92 against thespring retaining projection 96. Specifically, in the embodiment shown inFIG. 7 , an L-shapedspring retaining projection 96 extends axially inward frommember 66 of thebrush retainer 62, thereby defining aspring recess 98 in which anend 100 ofleg 92 may be inserted to allow thespring 84 to assume a preloaded condition as shown inFIG. 4 . Prior to placing thebrush 22 within thebrush retainer 62,leg 92 is compressed so that it clears thebrush retainer 62 and any extending portion of thebrush 22. Once the brush is inserted within thebrush retainer 62, theleg 92 is placed in contact with the rear ofbrush 22 to urge thebrush 22 toward thecommutator 20. - As shown in
FIG. 9 , thebrush retainers 62 define anopen mouth 72 within theend plate assembly 42, which open toward thefan assembly 14 and extend into a portion of thecommutator receiver 48. The opening of themouth 72, allows cooling air from thefan assembly 14 to flow past thebrushes 22, andmotor 16 as will be described more completely below. To allow air to pass over thearmature 18, or other parts of themotor assembly 12, theend plate assembly 42 provides a pair ofcavities 104. Thesecavities 104 may be at least partially sealed from themouth 72, to prevent particulates generated from thebrushes 22 from being carried downstream into the other areas of themotor assembly 12. To further limit the passage of particulates into themotor assembly 12,dividers plate assembly 42. To further limit particulates from entering themotor assembly 12, a bead of sealant may be provided, which extendsadjacent cavities 104, and between thecavities 104 and eachmouth 72 of thebrush retainer 62. As shown, thedividers mouths 72, such that theplate portion 44 is separated into distinct regions. - Air drawn into the
shroud 34 by thefan assembly 14, is directed to themotor 16 by a diffuser assembly that is designated generally by the numeral 120. Thediffuser assembly 120 is interposed between thefan 28 and theend plate assembly 42 and is configured to be interchangeable with existing diffuser assemblies that are part of other motor-fan units 10. That is, thediffuser assembly 120 of the present invention is designed to cooperate withend plate assemblies 42 of varying motor-fan units 10 so that thebrushes 22 ofsuch unit 10 are sufficiently supported. As shown inFIGS. 10-16 , thediffuser assembly 120 includes abaffle plate 122 which provides afan side 123 which is opposite amotor side 124. Thefan side 123 is positioned adjacent thefan assembly 14 when the motor-fan unit 10 is assembled. Likewise, themotor side 124 is positioned adjacent theend plate assembly 42 and themotor assembly 12 when theunit 10 is assembled. Thebaffle plate 122 includes anouter edge 125 which joins thefan side 123 to themotor side 124 and the plate also provides acentral opening 126 extending therethrough. Thecentral opening 126 receives and seats thecommutator receiver 48 to allow contact between thecommutator 20 and thebrushes 22. Extending from themotor side 124 are a plurality of curvilinear vanes designated generally by the numeral 128. Thevanes 128 are spaced apart and each vane has aplate edge 129 connected to the motor side and aring edge 130 opposite the plate edge. Thecurvilinear vanes 128 are disposed about the outer periphery of themotor side 124. In particular, eachvane 128 provides anexternal portion 131 that extends radially outwardly from theouter edge 125 on themotor side 124 and aninternal portion 132 that extends from themotor side 124. Theadjacent vanes 124 form aport 134 therebetween. Avane support ring 135 connects the external portions of the curvilinear vanes to one another and, in particular, joins the respective ring edges 130 of eachvane 128. Thering 135 has aninner diameter edge 136 and anouter diameter edge 137. It will be appreciated that theinner edge 136 has a diameter equal to or somewhat greater than the diameter of theouter edge 125. Theinternal portions 132 of thecurvilinear vanes 128 collectively form a collection chamber designated generally by the numeral 138. The construction of thebaffle plate 122 is ideally suited for a molded construction, but it will be appreciated that other materials could be used in formation thereof. Accordingly, thecurvilinear vanes 128 are integral with thebaffle plate 122 and thevane support ring 135 to provide a sturdy and easily manufactured construction. - The
curvilinear vanes 128 may comprise radial turning vanes, wherein the number of vanes is equal to that of a prime number. It is believed that by having such an arrangement, thediffuser assembly 120 is able to reduce the harmonic interaction between thefan 14 and the diffuser at certain revolutions-per-minute multiples as thefan assembly 14 rotates. In general, many harmonics may be generated by air passing by over the surface of the diffuser vanes. For example, in arrangements where a diffuser utilizes a number of vanes not equal to a prime number, generated harmonics may occur at multiples of the smallest mathematical factor for the number of vanes present. In contrast, a diffuser having a number of vanes equal to that of a prime number only has two factors (i.e. the number 1 and the prime number itself). As such, the use of thediffuser 128 with a number of vanes equal to that of a prime number eliminates the factor harmonics that would otherwise be created by a diffuser with a number of vanes not equal to a prime number. - When the
unit 10 is assembled and themotor assembly 12 rotates thefan assembly 14, air is drawn in through theshroud intake 34 and into thefan assembly 14. Thefan assembly 14 exhausts the air radially such that it swirls around within the interior of the shroud and is redirected by thebaffle plate 122 and, in particular, thecurvilinear vanes 128. The air is guided through theports 134 and swirls about thecollection chamber 138 so that the air is forced radially inwardly toward thecentral opening 126 where it is then redirected so as to flow through thecavities 104 and other regions of theend plate assembly 42. Accordingly, the air drawn in through theshroud intake 136 is directed through themotor assembly 12 as needed for the end application. - Specifically, the
vanes 128 may comprise radial turning vanes and/or may be equal in number to that of a prime number. For example, the number of turningvanes 128 may total 23, 29, or 37, although any other suitable prime number of turningvanes 128 may be utilized. By having such an arrangement, thediffuser assembly 120 is able to reduce the harmonic interaction between thefan 14 and thediffuser 120 at certain rpm multiples as the motor-fan unit 10 is in operation. More specifically, as high velocity air departs from a vane the resulting airflow also includes a vortex component that shears against other nearby vanes resulting in noise. The generated noise has its largest magnitude at frequencies equal to the multiples of the fan revolutions per minute (rpm) and the number of diffuser vanes. Thus, by altering the number ofvanes 128 and/or the rpm of thefan 28 of the motor-fan unit 10, the noise frequencies with higher magnitudes may be shifted to different frequencies, thus minimizing the noise that would otherwise occur. As such, the noise generated by air passing through thediffuser 120 is thereby reduced. - Additionally as shown in
FIGS. 12-16 , thediffuser assembly 120 contains one or morebrush cap assemblies 139. Thebrush cap assemblies 139 may be made integral with thebaffle plate 122 during manufacturing of thediffuser 120, or may be connected to thebaffle plate 122 using known techniques, including but not limited to thermal welding, adhesives, or screw-type connection. Thebrush cap assemblies 139 are configured to coact with thebrush retainer 62 to trap thebrushes 22 therebetween. In general, thebrush cap assemblies 139 provide a surface that substantially closes theopen mouth 72 of thebrush retainer 62 located on theend plate assembly 42. To contact thebrushes 22, or otherwise penetrate the opening of themouth 72, the brush caps 139, taking on the form of a projection, may extend axially toward themotor assembly 12, beyond thevanes 128 to a desired extent. In one arrangement, thebrush cap assembly 139 will not extend such that its contact with thebrushes 22 would interfere with the proper assembly of the motor-fan unit 10. Thebrush cap assembly 139 generally conforms to the contours of themouth 72 of thebrush retainer 62, and may be toleranced to provide a clearance that would allow dust or particulates from thebrushes 22 to escape throughopen end 70 of thebrush retainers 62. By providing such clearance, dust build-up on thebrushes 22 is reduced, and the airflow generated by the motor-fan unit 10 is able to pass over and cool thebrush 22, thereby extending the life of thebrush 22 and themotor 16. Further, the air escaping thebrush retainer 62, at the radial interior extreme of thebrush retainer 62 at theopen end 70 facing thecommutator 20, flows over thecommutator 20, keeping it cooled. - As shown in
FIGS. 12-18 , thebrush cap assemblies 139 have a generally rectangular shape to conform to the rectangular opening of theopen mouths 72 of theend plate assembly 42. To channel air from thefan assembly 14 toward thebrushes 22, thebrush cap assemblies 139 may be provided withchannels 140. Thechannels 140 are formed betweenupstanding members motor side 124 of thediffuser 120.Members central opening 126 and may radially project to an extent into the opening. To accommodate the extension of thebrush cap members commutator receiver 48,recess window 146 may be formed on thecommutator receiver 48, as shown clearly inFIG. 7 . Advantageously, an interference or friction fit between themembers commutator receiver 48 may be used in coupling theend plate assembly 42 and thediffuser assembly 120 together. -
Upstanding members curvilinear vanes 128 to allow for proper attachment of thediffuser assembly 120 to theend plate assembly 42. Further,upstanding members vanes 128 to an extent, such that they extend into theopen mouths 72 defined bybrush retainers 62. As a result thediffuser 120 is capable of attachment to theend plate assembly 42.Upstanding member 142 may have a raisededge 148 sized to fill the gap or notch 78 between theplate portion 44 andmember 68 of thebrush retainer 62. In this way, thebrush cap assembly 139 encloses thebrushes 22 when theend plate 42 anddiffuser 120 are coupled to one another. Adjacent the raisededge 148,upstanding member 142 may be provided with alanding 150, which has the same height asupstanding member 144, thereby forming a recessed area that lies adjacent to thebrush 22 when thediffuser assembly 120 andend plate assembly 42 are joined. Thechannel 140, opens toward themotor assembly 12 between the landing 150 andupstanding member 144. This arrangement, allows air generated by thefan assembly 14 to be distributed across the exposedsurface 152 of thebrush 22 that lies adjacent thebrush cap assemblies 139 shown inFIG. 7 . The air directed through thechannels 140 allows heat from thebrushes 22 to be carried away, thus improving operation of themotor 16. - An alternative embodiment of the
brush cap assemblies 139 are shown inFIGS. 17 and 18 , which may be used in coupling thediffuser 120 to theend plate assembly 42. To supplement the interference or friction fit betweenbrush cap assembly 139 and the walls ofopen mouth 70 or surfaces ofcommutator receiver 48, thebrush cap assembly 139 may be provided with a projecting surface, generally indicated by the numeral 154, that performs a snap-lock function in connection with anattachment surface 156 provided by therecess window 146 of theend plate assembly 42. It will be appreciated that projectingsurface 154 may be one of a number of configurations commonly used in the art to perform a snap-lock function, including but not limited to a flexible tab, a rounded surface, or a tapered leadingsurface 158 and stopsurface 160 combination as shown inFIG. 17 . - As shown in
FIGS. 17 and 18 ,brush cap assemblies 139 may havetriangular projections 162 extending radially inward from eachmember tapered surface 158 ofprojection 162 slopes outwardly from amember diffuser 80. Astop surface 160 extends inwardly from the taperedsurface 158 and is located vertically onmembers diffuser 120 to theend plate 42, thetapered surface 158 causes gradual deflection ofmembers members brush cap assemblies 139 are fully inserted within theopen mouths 72 of thebrush retainers 62, thestop surface 160 engages theattachment surface 156, such thatend plate assembly 42 anddiffuser 120 are coupled together. - It will, therefore, be appreciated that one advantage of one or more embodiments of the present invention is that the noise and vane passage frequencies associated with air movement over the diffuser's vanes are reduced. Still another advantage of the present invention is that the diffuser plate is configured, such that, the diffuser is capable of replacing a previously installed diffuser of an existing motor-fan unit. Yet another advantages of the present invention is that the diffuser is able to support the brushes of the motor-fan unit without additional adjustment to the diffuser.
- Although the present invention has been described in considerable detail with reference to certain embodiments, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.
Claims (22)
1. A diffuser interposed between a shrouded fan assembly and a motor assembly having a shaft that rotates a fan carried within said shrouded fan assembly, the diffuser comprising:
a baffle plate having a motor side and a fan side, said baffle plate having an opening therethrough; and
a plurality of vanes extending from said motor side, each said vane having an external portion which radially extends from said baffle plate, wherein adjacent vanes have a port therebetween, said plurality of vanes directing airflow generated by the fan from said fan side through said ports to said motor side.
2. The diffuser according to claim 1 , wherein each said vane has an internal portion contiguous with said external portion, said internal portions extending toward said opening.
3. The diffuser according to claim 2 , wherein said vanes are curvilinear and spaced apart from each other.
4. The diffuser according to claim 2 , wherein said internal portions terminate prior to reaching said opening so as to collectively form a collection chamber for the airflow.
5. The diffuser according to claim 1 , wherein each said vane has a plate edge at said motor side and ring edge opposite said plate edge.
6. The diffuser according to claim 5 , further comprising:
a vane support ring connected to at least some of said vanes.
7. The diffuser according to claim 6 , wherein said vane support ring is connected to at least some of said ring edges, said vane support ring having an inner edge with a diameter at least equal to or larger than said baffle plate's diameter.
8. The diffuser according to claim 1 , wherein each said vane comprises a radial turning vane.
9. The diffuser according to claim 1 , wherein said baffle plate is annular.
10. The diffuser according to claim 1 , wherein said plurality of vanes total a number equal to a prime number.
11. The diffuser according to claim 1 , further comprising:
at least one brush cap connected to said motor side of said baffle plate.
12. A motor-fan assembly comprising:
a field winding;
an armature having a shaft, said armature rotatably mounted within said field winding;
a fan attached to said shaft; and
a diffuser interposed between said fan and said field winding, said diffuser comprising:
a baffle plate having a motor side and a fan side;
said baffle plate having an opening therethrough;
a plurality of vanes extending from said motor side;
each said vane having an external portion which radially extends from said baffle plate wherein adjacent vanes have a port therebetween; and
said plurality of vanes directing airflow generated by the fan from said fan side through said ports to said motor side.
13. The motor assembly according to claim 12 , wherein each said vane has an internal portion contiguous with said external portion, said internal portion extending toward said opening.
14. The motor assembly according to claim 13 , wherein said vanes are curvilinear and spaced apart from each other.
15. The motor assembly according to claim 13 , wherein said internal portions terminate prior to reaching said opening so as to collectively form a collection chamber for the airflow.
16. The motor assembly according to claim 12 , wherein each said vane has a plate edge at said motor side and ring edge opposite said plate edge.
17. The motor assembly according to claim 16 , further comprising:
a vane support ring connected to at least some of said vanes.
18. The motor assembly according to claim 17 , wherein said vane support ring is connected to at least some of said ring edges, said vane support ring having an inner edge with a diameter at least equal to or larger than said baffle plate's diameter.
19. The motor assembly according to claim 12 , wherein each said vane comprises a radial turning vane.
20. The motor assembly according to claim 19 , wherein said plurality of radial turning vanes total a number equal to a prime number.
21. The motor assembly according to claim 12 , wherein said baffle plate is annular.
22. The motor assembly according to claim 12 , wherein said plurality of vanes total a number equal to a prime number.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US11/193,908 US20070025848A1 (en) | 2005-07-29 | 2005-07-29 | Reduced noise diffuser for a motor-fan assembly |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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US11/193,908 US20070025848A1 (en) | 2005-07-29 | 2005-07-29 | Reduced noise diffuser for a motor-fan assembly |
Publications (1)
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US20070025848A1 true US20070025848A1 (en) | 2007-02-01 |
Family
ID=37694480
Family Applications (1)
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US11/193,908 Abandoned US20070025848A1 (en) | 2005-07-29 | 2005-07-29 | Reduced noise diffuser for a motor-fan assembly |
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US (1) | US20070025848A1 (en) |
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US20140212304A1 (en) * | 2013-01-28 | 2014-07-31 | Robert E. Michael | Blower assembly for hand dryer |
CN104121228A (en) * | 2013-04-24 | 2014-10-29 | 哈米尔顿森德斯特兰德公司 | Turbine nozzle piece parts with HVOC coatings |
US20160238033A1 (en) * | 2015-02-13 | 2016-08-18 | Johnson Electric S.A. | Noise Reduction Diffuser for an Electric Blower |
US11378309B2 (en) * | 2019-10-08 | 2022-07-05 | B/E Aerospace, Inc. | Multi-stage vortex tube assembly for low pressure and low flow applications |
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US9284963B2 (en) * | 2013-01-28 | 2016-03-15 | American Dryer, Inc. | Blower assembly for hand dryer, with helmholtz motor mount |
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US20160238033A1 (en) * | 2015-02-13 | 2016-08-18 | Johnson Electric S.A. | Noise Reduction Diffuser for an Electric Blower |
US10184490B2 (en) * | 2015-02-13 | 2019-01-22 | Johnson Electric S.A. | Noise reduction diffuser for an electric blower |
US11378309B2 (en) * | 2019-10-08 | 2022-07-05 | B/E Aerospace, Inc. | Multi-stage vortex tube assembly for low pressure and low flow applications |
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