Patent Grant
10393129
The present invention relates generally to a blower wheel and shaft assembly for use in a high-efficiency furnace or other application.
Those of ordinary skill in the art will appreciate that a secure interconnection between a shaft and the structure or structures it supports is conventionally desirable. In the case of a rotatable shaft and blower wheel in a high-efficiency furnace, for instance, interconnection of the shaft and blower wheel is conventionally facilitated by means of a metal insert that is overmolded into the plastic blower wheel and then coupled to the metal shaft via an interference fit (i.e., press fit) such that the shaft and blower wheel are simultaneously rotatable.
According to one aspect of the present invention, a blower motor assembly is provided for use in a machine. The motor assembly comprises a blower wheel including a hub. The motor assembly further comprises a motor including a shaft rotatable about an axis. The hub is an integral part of the blower wheel. The hub presents a cylindrical, radially inner hub surface that at least in part defines a cylindrical hub opening. The inner hub surface defines an inner diameter. The shaft is axially received within the hub opening, such that the blower wheel is supported by the shaft for rotational movement. The shaft includes a toothed region defining a plurality of arcuately spaced apart teeth. Each of the teeth includes a primary body and a cutting portion. Each of the teeth has an apex and a pair of sides extending from the apex. The cutting portion of each tooth defines the apex and a radially outer portion of each of the sides. The primary body of each tooth defines a radially inner portion of each of the sides. The primary body of each tooth is disposed radially inwardly of the inner hub surface. Each of the cutting portions presents a cutting edge. The cutting portions of the teeth cooperatively present an outer cross-sectional dimension that is greater than the inner diameter of the inner hub surface, such that the cutting edges of the teeth cut a plurality of grooves in the inner hub surface as the shaft is axially received in the hub opening. The cutting portions of the teeth are received in the grooves formed thereby and thus are configured to transmit torque from the shaft to the hub.
This summary is provided to introduce a selection of concepts in a simplified form. These concepts are further described below in the detailed description of the preferred embodiments. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
Various other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying drawing figures.
Preferred embodiments of the present invention are described in detail below with reference to the attached drawing figures, wherein:
The drawing figures do not limit the present invention to the specific embodiments disclosed and described herein. The drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the preferred embodiments.
Furthermore, directional references (e.g., top, bottom, front, back, side, etc.) are used herein solely for the sake of convenience and should be understood only in relation to each other. For instance, a component might in practice be oriented such that faces referred to as “top” and “bottom” are sideways, angled, inverted, etc. relative to the chosen frame of reference.
The present invention is susceptible of embodiment in many different forms. While the drawings illustrate, and the specification describes, certain preferred embodiments of the invention, it is to be understood that such disclosure is by way of example only. There is no intent to limit the principles of the present invention to the particular disclosed embodiments.
With initial reference to
The blower motor 12 preferably includes a stator 18 and a rotor 20 rotatable about an axis. The rotor 20 preferably includes a shaft 22 rotatable about an axis. The blower wheel 14 is preferably supported by the shaft 22 for rotational movement therewith. In a preferred embodiment, the motor 12 is operable to rotate the shaft 22, which in turn rotates the blower wheel 14. The blower wheel 14 generates airflow that is directed by the housing 16.
The principles of the present invention are equally applicable to the blower wheel 14 being supported by a shaft other than the rotor shaft 22, as illustrated. For example, the motor may alternatively be provided with an output shaft which is drivingly connected to the rotor shaft, with the blower wheel being supported on the output shaft. A transmission may also be provided, if desired, with the blower wheel being alternatively supported on one of the shafts of the transmission.
The motor 12 is preferably an induction motor but may be of any type known in the art without departing from the scope of the present invention. For instance, the motor might alternatively be a brushless permanent magnet motor.
Most preferably, the blower wheel 14 is a draft inducer blower wheel and the blower motor 12 is for use in a high-efficiency furnace. Other applications are permissible, however.
The motor 12 is preferably secured on the housing 16 by means of a mounting bracket 24, shown in
The housing 16 preferably includes a plurality of mounting bosses 26 through which fasteners 28 extend for securing the entire blower motor assembly 10 to a machine (not shown). The machine is preferably a high-efficiency furnace, although other machines are permissible.
The housing 16 preferably includes first and second halves 30 and 32, respectively, although an integrally formed housing or one comprising more than two (2) segments may be provided without departing from the scope of the present invention.
The housing 16 preferably defines a cylindrical wheel chamber 34 and an outlet 36 fluidly interconnected with the wheel chamber 34. The wheel chamber 34 preferably receives the blower wheel 14. The outlet 36 preferably extends generally tangentially relative to the wheel chamber 34. Other housing forms are permissible, however. For instance, the wheel chamber might alternatively be generally cuboidal or include an additional outlet.
As best shown in
The blower wheel 14 preferably comprises a plastic or synthetic resin material, although the use of one or more other materials is permissible according to some aspects of the present invention. More particularly, as will be discussed in greater detail below, specific materials are of less importance than the relative properties of the material(s) constituting certain regions of the blower wheel 14 and the shaft 22.
Preferably, the blower wheel 14 is formed by one or more molding processes (e.g., one molding process for formation of the front plate 38 and one molding process for formation of the rear plate 40). However, use of additional or alternative processes (e.g., machining and/or stamping, as might be required if some of all of the blower wheel were formed of metal) is permissible according to some aspects of the present invention.
As illustrated in
In a preferred embodiment, a plurality of arcuately spaced apart, generally radially extending blades 52 project axially outwardly from the front plate 38, away from the vanes 42 and the rear plate 40. The blades are preferably evenly arcuately spaced apart, although uneven spacing is permissible.
Each blade 52 preferably extends from a location in the intermediate region 50 to a location at or near the radially outermost margin 46 of the front plate 38. It is permissible, however, for the blades to be alternatively positioned (e.g., nearer the hub region than the rim region).
The blades 52 are preferably integrally formed with the front plate 38, although non-integral configurations are permissible. For instance, the blades might alternatively snap into place or be fastened or adhered to the front plate.
As best shown in
The front plate 38 is preferably formed in a molding process that includes formation of the balancing nubs 54, with the axial height of each nub 54 varying depending on the position of a corresponding balancing screw or other shiftable structure in the mold itself during the process. For instance, if a given balancing screw is turned so as to shift the screw axially inwardly prior to molding, the resulting molded balancing nub will have a smaller axial height. In contrast, if the balancing screw is turned so as to shift the screw axially outwardly prior to molding, the balancing nub 54 will have a greater axial height. The heights of the nubs are preferably varied as necessary to ensure the blower wheel 14 as a whole is balanced upon removal from the mold. That is, material removal and/or other post-molding procedures are preferably not required for production of a balanced blower wheel, with the molding process alone preferably being sufficient.
Although provision of balancing nubs 54 as described above is preferred, it is permissible according to some aspects of the present invention for alternative or additional means of balancing to be provided and/or utilized, including but not limited to post-molding material removal processes.
As best shown in
The rear plate 40 preferably defines a plurality of radially inner connecting pin openings 62 and a plurality of radially outer connecting pin openings 64. The respective pluralities of inner and outer connecting pin openings 62 and 64 are preferably evenly arcuately spaced apart, although uneven and/or non-arcuate spacing of either or both pluralities of openings is permissible according to some aspects of the present invention. Furthermore, alternative groupings or arrangements (i.e., non-radially-based groupings) or no groupings or arrangements at all (e.g, an even distribution or a random distribution) are permissible according to some aspects of the present invention. The connecting pin openings 62 and 64 will be discussed in greater detail below.
The rear plate 40 further preferably defines a locating hole 66. The locating hole 66 will also be discussed in greater detail below.
As noted previously, the front and rear plates 38 and 40, respectively, are preferably axially spaced apart and interconnected by the generally radially extending, arcuately spaced apart vanes 42. As best shown in
Preferably, each vane extends from a location in the hub region 48 to a location at or near the radially outermost margin 46. However, it is permissible for some or all of the vanes to extend a different degree. For instance, alternating ones of the vanes might instead extend from a location in the intermediate region to a location at or near the radially outermost margin.
In a preferred embodiment, the vanes 42 are curved for aerodynamic optimization. That is, each vane 42 is generally radially extending (as noted previously) but also includes some degree of circumferential extension so as to extend both radially and circumferentially. However, it is permissible for straight or otherwise configured vanes to be provided without departing from the scope of the present invention.
Furthermore, although it is preferred that each of the vanes 42 be identically shaped and sized, variations are permissible. For instance, alternating ones of the vanes could be curved more or less than the others, or some of the vanes could extend a shorter distance.
The vanes 42 are preferably integrally formed with the front plate 38, although non-integral interconnection (e.g., by means of fasteners and/or adhesives) is permissible according to some aspects of the present invention.
As best shown in
In keeping with the alternative arrangements discussed above with regard to the connecting pin openings 62 and 64, alternative groupings or arrangements (i.e., non-radially-based groupings) or no groupings or arrangements at all (e.g, an even distribution or a random distribution) of the pins are permissible according to some aspects of the present invention. Preferably, however, the pins and openings correspond to each other to at least some extent.
Referring again to
As noted previously, the rear plate 40 preferably defines a locating hole 66. Alignment of the locating pin 72 and the locating hole 66 during the assembly process enables efficient subsequent alignment of the connecting pins 68 and 70 with the corresponding connecting pin openings 62 and 64 (see
Alternative means of appropriately orienting the rear plate are permissible without departing from the scope of some aspects of the present invention, however.
As best shown in
The blower wheel 14 further preferably includes a hub 76. As will be discussed in greater detail below, the hub 76 at least in part receives the shaft 22.
The hub 76 is preferably an integral part of the blower wheel 14. More particularly, the hub 76 is preferably integrally formed with the front plate 38.
The shaft 22 preferably includes a driven end 78 adjacent the stator 18, a blower end 80 spaced axially from the driven end 78 and adjacent the blower wheel 14, and a main body 82 extending between and interconnecting the driven end 78 and the blower end 80.
The main body 82 is preferably secured snugly to the hub 76 via a press fit or friction fit, although other types of fit (e.g., a slip fit) are permissible according to some aspects of the present invention. As will be described, the shaft 22 and the hub 76 are further connected by additional means other than just the press fit or friction fit. That is, the hub 76 is preferably secured to the shaft 22 by multiple interconnections, including the aforementioned press fit or friction fit and additional means to be discussed below.
As best shown in
As will be discussed in greater detail below, the leading end 94 preferably includes a circumferentially extending first angled deflection face 110 and a circumferentially extending, generally axial slip face 112 disposed between the third recess 96 and the first angled deflection face 110.
In a preferred embodiment, the first angled deflection face 110 is oriented between about fifteen degrees (15°) and about forty-five degree (45°) relative to the axis. Most preferably, the first angled deflection face 110 is oriented about thirty degrees (30°) relative to the axis.
The first angled deflection face 110 and the slip face 112 each preferably extend continuously circumferentially, although discontinuous extension is permissible according to some aspects of the present invention.
The toothed region 84 preferably defines a plurality of arcuately spaced apart teeth 86. The teeth 86 are preferably evenly arcuately spaced apart, although uneven spacing is permissible according to some aspects of the present invention.
The teeth 86 are preferably generally axially extending, although helical or other types of extension are permissible according to some aspects of the present invention.
As best shown in
The sides 116 of each tooth 86 are preferably straight and at least substantially perpendicular to each other. That is, an angle of about ninety degrees (90°) is preferably formed between each pair of sides 116 adjacent the corresponding apex 114. It is permissible according to some aspects of the present invention, however, for non-straight and/or non-perpendicular sides to be provided. For instance, the sides might be convex or concave, or the angle between respective pairs of sides might be sixty degrees (60°). Furthermore, the teeth might be in an entirely alternative form. For instance, the teeth might be in the form of splines or rectangular keys.
The teeth 86 are preferably all identically configured, although the teeth may vary in shape and/or size according to some aspects of the present invention.
As will be discussed in greater detail below, regardless of the general configuration of the teeth, it is preferable that the teeth 86 be configured in such a manner as to retain a high degree of structural integrity. That is, very narrow or otherwise non-robust teeth (i.e., teeth prone to a significant degree of deflection or other degradation during assembly of the motor assembly, as will be discussed in greater detail below) are not preferred.
The shaft 22 preferably comprises metal, although any one or more of a variety of suitable materials may be used without departing from the scope of some aspects of the present invention. More particularly, as noted previously and as will be discussed in greater detail below, specific materials are of less importance than the relative properties of the material(s) constituting certain regions of the blower wheel 14 and the shaft 22.
As noted previously, the blower wheel 14 preferably includes an integrally formed hub 76 that at least in part receives the shaft 22. More particularly, the hub 76 preferably presents a radially inner hub surface 118 that at least in part defines a hub opening 120. The shaft 22 is axially received in the hub opening 120. Most preferably, as will be discussed in greater detail below, the hub opening 120 at least substantially receives the blower end 80 and further receives a portion of the main body 82 of the shaft 22.
The hub 76 is configured such that receipt of the shaft 22, beginning with the leading end 94, causes the formation of grooves 122 in the inner hub surface 118. More particularly, each tooth 86 preferably includes a cutting edge 124 that cuts a corresponding one of the grooves 122 upon relative axial shifting of the shaft 22 and the hub 76 (e.g., by axial shifting of the shaft 22 relative to the stationary hub 76 such that the shaft 22 is received in the hub opening 120.).
In more detail, the inner hub surface 118 preferably defines a inner cross-sectional dimension. The teeth 86 preferably present an outer cross-sectional dimension that is greater than the inner cross-section dimension of the inner hub surface 118. Such interference-causing dimensional disparity is such that the cutting edges 124 of the teeth 86 cut the plurality of grooves 122 in the inner hub surface 118 as the shaft 22 is axially received in the hub opening 120.
It is noted that “cut” as used herein should be understood as referring to any mechanical means by which the pre-existing interference between parts is overcome (e.g., material removal, deformation, and/or relocation). Furthermore, “cutting edge” should be understood to be any portion enacting such cutting. For instance, while the cutting edge may comprise a sharp point or ridge, it may additionally or alternatively include a flat surface operable to push or compress an adjacent material. Such surface may be oriented in any operable manner. For instance, the surface might be oriented orthogonally relative to the axis or be angled obliquely relative thereto to form a tapered profile. In the illustrated embodiment, for instance, the cutting edge 124 of a given tooth 86 includes a generally radially extending flat surface that engages the hub 76 to push material aside for formation of the corresponding groove 122. The sides 116 of each tooth 86 direct the material and thereby constitute part of the cutting edge, as well.
Preferably, the inner cross-sectional dimension of the inner hub surface 118 is between about five thousandths (0.005) inches and fifteen thousandths (0.015) inches smaller than the outer cross-sectional dimension of the teeth 86. Most preferably, the inner cross-sectional dimension of the inner hub surface 118 is about nine thousandths (0.009) inches smaller than the outer cross-sectional dimension of the teeth 86. It is permissible according to some aspects of the invention, however, for the degree of interference to vary. For instance, variations in cutting edge configuration and/or material selection for the hub and the shaft might result in a different degree of interference being optimal.
In a preferred embodiment, the toothed region 84 has a generally circular cross-sectional shape with an outer diameter that presents the outer cross-sectional dimension. Furthermore, the inner hub surface 118 is preferably at least substantially circular in cross-section to present an inner diameter that defines the inner cross-sectional dimension.
Preferably, the inner and outer dimensions (or, more preferably, the inner and outer diameters) are axially constant, although tapering or other variations are permissible according to some aspects of the present invention.
In keeping with the preferred tooth 86 configuration described above, the grooves 122 are preferably generally axially extending and evenly arcuately spaced apart, although such preferred arrangement may vary in keeping with the above-describe permissible variations in the configuration of the teeth.
Preferably, the teeth 86 and the hub 76 comprise dissimilar materials, with the hub 76 comprising a relatively softer material conducive for cutting by the relatively harder material of the teeth. More preferably, the entire shaft 22 and the entire blower wheel 14 comprise dissimilar materials, with the blower wheel 14 comprising a relatively softer material conducive for cutting by the relatively harder material of the shaft 22. As noted above, it is preferred for the shaft 22, and particularly the teeth 86, to be formed of metal. In contrast, it is preferred for the blower wheel 14, and particularly the hub 76, to be formed of plastic.
In a preferred embodiment, the hub 76 includes a plurality of axially extending, resiliently deflectable tabs 126 and a plurality of flanges 128. Each flange 128 preferably extends generally radially inwardly from a corresponding one of the tabs 126. The tabs 126 (and, in turn, the flanges 128) are preferably evenly arcuately spaced apart, although uneven or otherwise alternative arrangements are permissible according to some aspects of the present invention.
The flanges 128 each preferably define a second angled deflection face 130, to be described in greater detail below. As best shown in
More particularly, the flanges 128 preferably cooperatively define a flange opening 132. When the tabs 126 are in an undeflected position, the flange opening 132 has an outer diameter that is smaller than that of the slip face 112 of the leading end 94. That is, the slip face 112 cannot pass through the flange opening 132 unless the flange opening 132 is expanded. Such resilient expansion is illustrated in
As noted previously, the first angled deflection face 110 is preferably oriented between about fifteen degrees (15°) and about forty-five degree (45°) relative to the axis. Most preferably, the first angled deflection face 110 is oriented about thirty degrees (30°) relative to the axis. The second angled deflection face 130 is preferably oriented between about thirty degrees (30°) and about sixty degrees (60°) relative to the axis. Most preferably, the second angled deflection face 130 is oriented about forty-five degrees (45°) relative to the axis
As best shown in
Alternatively, the tabs and flanges may be configured such that the tabs remain resiliently flexed when the flanges are received in the recess, with the tabs thereby providing a generally radially inward compressive force that aids the flanges in “gripping” the shaft.
Upon receipt of the flanges 128 in the third recess 96, the flanges 128 and the shoulders 106 and 108 preferably cooperatively restrict relative axial movement between the hub 76 and the shaft 22.
Although it is preferred that the third recess 96 is in part defined by a pair of shoulders 106 and 108, with the two shoulders 106 and 108 cooperatively restricting movement of the hub 76 and shaft 22 as described above, it is permissible according to some aspects of the present invention for only one of the shoulders to restrict such motion and/or for the third recess to be associated with only one shoulder. For instance, in an alternative embodiment, only an inward-facing shoulder (e.g., the shoulder 108) might be provided, with the inward-facing shoulder cooperating with the flanges to prevent the blower wheel from shifting off the blower end of the shaft. However, an additional outward-facing shoulder (e.g., the shoulder 106) is most preferably provided, so that axial movement of the wheel relative to the shaft is limited in both axial directions.
In a preferred embodiment, as best shown in
Thus, as will be apparent from the above description, it is most preferable that the shaft 22 and the blower wheel 14 are interconnected by three (3) primary means: the tight fit (e.g., press fit or friction fit) of the main body 82 of the shaft 22 in the hub opening 120; the engagement of the teeth 86 of the shaft 22 with the grooves 122 (formed in the hub 76 by means of the cutting edges 124 of the teeth 86); and the locking effect of the tabs 126 and the flanges 128, particularly in cooperation with the shoulders 106 and 108.
A second preferred blower motor assembly 210 is illustrated in
The blower motor assembly 210 of the second embodiment preferably includes a blower motor 212, a blower wheel 214, and a housing 216. The blower motor 212 preferably includes a stator (not shown) and a rotor 218 rotatable about an axis. The rotor 218 preferably includes a shaft 220 rotatably supporting the blower wheel 214.
The blower wheel 214 preferably includes an integrally formed hub 222 that at least in part receives the shaft 220. The hub 222 preferably includes a plurality of axially extending, resiliently deflectable tabs 224 and a plurality of flanges 226. Each flange 226 preferably extends generally radially inwardly from a corresponding one of the tabs 224.
The hub 222 further preferably includes an axially projecting collar 228 extending about the tabs 224 and the flanges 226. Preferably, the collar 228 comprises a circumferential wall that at least substantially circumscribes the tabs 224 and the flanges 226. However, alternative shapes are permissible. For instance, the collar might instead form a rectangle about the flanges and tabs.
The collar 228 preferably extends continuously circumferentially, although discontinuous extension is permissible according to some aspects of the present invention.
In a preferred embodiment, as best shown in
Although a generally flush configuration is preferred, the collar may alternatively extend axially past the endmost margins of the tabs or be recessed relative to the endmost margins. Preferably, however, the collar provides at least some degree of structural protection to the tabs and/or the flanges.
The preferred forms of the invention described above are to be used as illustration only and should not be utilized in a limiting sense in interpreting the scope of the present invention. Obvious modifications to the exemplary embodiments, as hereinabove set forth, could be readily made by those skilled in the art without departing from the spirit of the present invention.
The inventors hereby states their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention set forth in the following claims.
The present application is a continuation of U.S. patent application Ser. No. 14/679,838 filed Apr. 6, 2015, and entitled DRAFT INDUCER BLOWER WHEEL HAVING IMPROVED SHAFT CONNECTION, the entire disclosure of which is hereby incorporated by reference herein.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4763031 | Wang | Aug 1988 | A |
| 5938405 | Coleman | Aug 1999 | A |
| 9206825 | Lei | Dec 2015 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| 20180306197 A1 | Oct 2018 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14679838 | Apr 2015 | US |
| Child | 16023907 | US |
