INSERT FOR FAN MOTOR ASSEMBLY TECHNICAL FIELD The present invention is directed generally to motor assemblies. In particular, the present invention is directed to a motor insert for a protected fan motor assembly which increases the motor efficiency and air flow characteristics. Specifically, the present invention relates to an insert which is received in a cavity created by an end clamp and fan cover and is adaptable to be placed in existing designs.
BACKGROUND TECHNIQUE Vacuum motors that employ a tangential deviation are used in many applications such as vacuum handlers, packaging equipment, bag filling, cutting tables, appliances and exhaust air removal, to name a few. These vacuum motor designs generally include a cylindrical housing, or cover, which encloses a fan driven by a motor that rotates about an axis. The air is drawn into the housing via an opening in the upper axial center of the housing above the fan. When the fan rotates, the air speeds up
in circumferential direction and radially outward. The housing provides a localized outlet on the side of the fan opposite the opening. The outlet is a generally cylindrical opening positioned tangentially on the radially end edge of the housing so that air moving circumferentially along the outer radial edge is expelled through the outlet in the tangential direction. These fans are efficient and have a small profile which allows them to be placed in devices that require a thin fan motor assembly. As with most fan designs, efficiency is an important aspect. Current housing designs do not direct the airflow in its most efficient path within the housing. Specifically, it is believed that turbulence and undesirable dead zones are generated by the uncontrolled path of the air flow from where air is expelled from the rotating fan to where the air exits through the outlet. The fan creates significant kinetic energy in the air imparting tangential velocity. The air must be decelerated in a controlled manner to convert the kinetic energy back to pressure. Sudden changes in the cross section
they can cause eddy currents and turbulence which dissipate the kinetic energy as heat instead of recovering it as pressure. The total pressure (or vacuum) created by the fan motor assembly is thus adversely affected by allowing the air to exit the fan in an uncontrolled manner. Therefore, there is a need to better manage the air flow to achieve higher fan efficiency. In addition, that better not only should be applicable to new fan assemblies, but also in a form that can be installed in fan assemblies that are already built, or in which the manufacturer already has a molding tool and does not want to modify it. Therefore, there is a need in the art for an insert that can be placed in the housing of a vacuum motor fan that employs a tangential deflection that directs the air flow and increases efficiency.
SUMMARY OF THE INVENTION In view of the above, a first aspect of the present invention is to provide a fan insert that achieves better efficiency. Yet another aspect of the present invention is to provide a fan assembly comprising a
end clamp which is coupled to a motor mount, the end clamp including a circumferential channel which is interrupted by an opening, a fan which includes a plurality of blades or blades, a cover which encloses the fan at least partially, and defines a chamber, an insert received in the chamber, the insert including a circumferential ramp which is received in the channel, where the circumferential ramp is configured to provide the channel with a cross-sectional area which varies circumferentially. Yet another aspect of the present invention is achieved by a motor assembly comprising an end clamp and an insert which is generally cylindrical and has a central axis where the insert includes a circumferential ramp which is placed in a helical direction relative to the axis, a cover coupled to the extreme clamp that defines a chamber between them, and a fan that rotates selectively by means of an axis, the fan is placed inside the chamber and generates an air flow that is forced along of the circumferential ramp.
BRIEF DESCRIPTION OF THE DRAWINGS For a complete understanding of the objectives,
Techniques and structure of the invention, reference will be made to the following detailed description and the accompanying drawings in which: Figure 1 is a perspective view of a fan / motor assembly made in accordance with the concepts of the present invention; Figure 2 is a partial cross-sectional view of the fan / motor assembly made in accordance with the concepts of the present invention; Figure 3 is an exploded view of an end clamp and an insert made in accordance with the concepts of the present invention; Figure 4 is a top elevational view of the end bracket; Figure 5 is a top elevational view of the end clamp with the insert installed; Figure 5A is a top elevational view of the insert; Figure 6 is a perspective view of the insert showing the underside thereof; Figure 7 is a perspective view of the end clamp with the insert installed.
BEST MODE FOR CARRYING OUT THE INVENTION A fan insert according to the
The concepts of the present invention, indicated generally by the numeral 80 in the accompanying drawings, are used in conjunction with an engine / fan assembly generally indicated by the numeral 10 in the accompanying drawings. Since the insert 80 can be used in connection with one of the other similarly constructed motor / fan assemblies, reference will generally be made only to the components of the motor / fan assembly other than those directly involved with the insert 80. As best seen in Figures 1 and 2, the motor / fan assembly 10 of the present invention includes a motor subassembly 11 and fan sub-assembly 12. It will be appreciated that, except for the fan end clamp, generally designated by the number 21 and described later in greater detail, the motor sub-assembly 11 can be of any suitable conventional construction. In a particular embodiment, the engine sub-assembly 11 includes a housing 13. The housing 13 may contain a concentrically positioned bearing 114 which receives an arrow shaft 15 therein. The shaft 15 supports an armature 16 and a switch 17 thereon. The shaft 15 also contains a cooling fan 18, which is placed on the end of the shaft 15 opposite the sub-assembly 12. The
Cooling fan 18 provides an air flow over internal engine components that provide heat dissipation. The motor sub-assembly further includes a plurality of field coils 19 as well as a plurality of brushes 20. As shown in the art, those motor components interact to cause the shaft 15 to rotate selectively. As will be described hereinafter, the shaft 15 drives the working components of the fan sub-assembly. In one embodiment, an end bracket 21 is provided on the end of the motor subassembly 11 opposite the housing 13. The end bracket 21 may be generally circular and is provided to allow the fan components to be coupled to the sub-assembly of the motor 11. Additionally the end clamp 21 separates the motor sub-assembly 11 from the fan sub-assembly 12 sealing around the shaft 15 in such a way that the air flow generated by the fan sub-assembly is not contaminated by air or other material of the motor sub-assembly. The end clamp 21 can be provided with a plurality of ears 22 or slots 23 by means of which an associated apparatus can be fastened and indexed in a position selected by these or by an end-use manufacturer. The end clamp 21 includes an end flange 24 on
which defines the extreme radial surface thereof. The outer rim 24 can be provided with a raised rim 25 which projects radially from and circumferentially around the outer rim 24. The rim 25 is provided as a touch, against which sits a rim of a cover 26. In this way, the cover 26 is received around the outer rim 24 forming a seal generally air tight. As will be discussed later and in greater detail, the cover 26, in cooperation with the external clamp 21 forms a first chamber 27 which receives some of the working components of the fan. The outer clamp 21 is further provided with an internal plate 28 which is generally circular and extends radially, facing the first chamber 27. The internal plate 28 terminates at its radial outer edge in an internal rim 29 from which it extends perpendicularly from the inner plate 28. The inner flange 29 also extends beyond the inner plate 28 and provides a flange 30 which can support the insert 80 as will be described hereinafter. The inner flange 29, together with the outer flange 24 provides the two generally opposite side walls of a circumferential channel 31. The channel 31 is ring-shaped, having a section
transverse generally U-shaped with a lower surface 32 and lateral walls defined by the flanges 24 and 29. A pair of radial edges 33 can transit between the lower surface 32 and the flanges 24 and 29. The internal plate 28 also includes an opening of axis 33 through it. The channel 31 is interrupted by a portion of its outer periphery and extends into an opening 41 (better seen in Figure 4) which is formed by a tangential horn 42, which can be integrally molded or otherwise extended from the clamp 21. The horn 41 preferably extends beyond the outer rim 24 and terminates a tubular portion 43 which can receive a discharge hose for working the air directed through the fan sub-assembly 12. The inner rim 29 and the inner plate 28 serve as a common wall between the fan assembly 12 and the sub-assembly of the motor 11 and through which the common shaft 15 which is operatively coupled to the aforementioned motor elements extends. Accordingly, a support ring 45 is provided, which is oriented towards the motor sub-assembly 11, in the center of the inner plate 28 around the opening of the shaft 33, both of which are adapted to receive a bearing 46 in they. He
Bearing 46 is adapted to receive and support the shaft 15 which rotates therein. The support ring 45 also extends axially from the internal plate 28, defining a projection 47 which extends towards the first chamber 27. A seal 48 can be captured between the bearing 48 and the support ring 45 and / or the projection 47 to avoid contamination of the air passing through the fan subassembly. The seal 48 can be in any of a number of ways. In fact, the seal could use the teachings of U.S. Patent Nos. 5,482,378 and / or 6,472,786, both of which are incorporated herein by reference. The end clamp of the fan 21 is further provided with a plurality of alignment tabs 50 which are circumferentially spaced apart and extend radially inwardly from the outer rim 24 towards the channel 31. In addition, the inner plate 28 can in fact be provided with a plurality of holes 51, each of which are adapted to receive securing means. In the present embodiment the securing means is described as a threaded screw 52, although other securing means such as rivets, adhesive, snap fit, pliers, collapsible tabs and friction interfaces may be used. As will be
discussed more fully below, the tabs 50 and the holes 51 are provided to align and secure the insert 80 within the first chamber 27. The cover 26 is provided with a hole 60 which is substantially concentric with the axis 15. orifice 60 is provided to allow working the air entering the fan subassembly 12. The cover 26 encloses at least one of a plurality of fans, one or more bearings nearby 46 being a spinning centrifugal fan. This fan 61 is comprised of a plurality of relatively short, radially-spaced vanes 62 mounted on a disk 63, the latter having a central hole allowing the fan 61 to be mounted to the shaft 15. The disk 63 is spliced against and rotates with the first centrifugal working air fan 64 which has a plurality of vanes 65 extending radially outwards. The vanes 65 are held between a disk 66 and a ring 99, where the disk 66 has a central hole that allows the first working fan 64 to be mounted to the shaft 15. The ring 99 has an air flow opening 100 that is extends through it. In the case that an air seal construction is used, as described in U.S. Patent No. 5,482,378, then disk 66 may
be provided with one or more openings that are circumferentially spaced relative to the axis. These openings work to extract moisture from the bearing in such a way that it is drawn into the working and expelled air flow. In the embodiment shown, the cover 26 encloses not only the fans 61 and 64, but additional fans for extracting the working air towards the fan subassembly 12. This multiple cover mode is possible by providing the cover 26 with a dividing wall 67 which extends radially inward from the radially outer wall of the cover 26. The divider wall 67 is provided with an opening 68 which leads to an air flow opening 100 of the working fan 64. In this way the partition wall 67 separates the inside of the fan subassembly towards the chamber 27 and a second chamber 69. The divider wall 67 supports, radially toward the aperture 68, the fixed radially extending vanes 70 of a "stationary fan" 71 intermediate. provides a second centrifugal work fan 72 near the orifice 60 and includes a plurality of vanes 73 which extend radially. bés 73 are supported between a disk 74 having a central hole that allows the
fan 72 is mounted to shaft 15 and a ring 104 having an eye 106 that is substantially concentric with hole 60 in cover 26. Although in this embodiment multistage fans are shown, it will be appreciated that the insert to be discussed could be used with a single stage fan, or any combination that receives air axially and then ejects the air tangentially, or vice versa. In the present embodiment, the aforementioned fans are separated and coupled to the shaft 15 by a plurality of elements. A first separator 75 extends inwardly through the opening of the shaft 33 in the support ring 45 and rests against an inner race of the bearing 46. The first separator 75 may have a generally L-shaped cross section to provide a surface elongated crosspiece against which the disk 63 of the fan 61 can rest. Placed between the working air fans 64 and 72 is a second separator 76 which is received on the shaft 15 and, in a radial cross section, can generally have a clock glass configuration. A nut 77 can be provided at the end of the shaft 15 which can be pressed against a collar 78 which in turn rests against the disk 74 of the fan 72. This a
in turn holds the inner track of the bearing 46, the first separator 75, the second separator 76, the fans 61, 64 and 72 and the collar 78 so that all at once form a unit with the shaft 15 when driven by the motor sub-assembly 11. In this way, when the shaft 15 rotates, the air is drawn into the second chamber 29 of the orifice 60. When the second working fan 72 rotates, air is drawn through the eye 106 and is pushed radially. outwardly by the vanes 73. Once the air is ejected radially outwards along the vanes 73, the vanes 70 of the stationary fan 71 direct the air flow radially inward towards the opening 68. As is evident from Figure 2, the opening 68 directs a flow of air to the first chamber 27 via the air flow opening 100. When the fan 64 rotates, the blades 65 push the air radially outward. The air flow that is ejected radially from the vanes 65 has a radial and a tangential component. In other words, the air particles move radially outwards while at the same time rotating with the fan 64. In this way, when the air leaves the fan 64, if the fan is moving in a direction opposite to the hands of the watch (as contemplated in this
mode), the air is moved, correspondingly circumferentially in a counter-clockwise direction around the chamber 27 and likewise the channel 31. Due to the pressure difference between the external atmosphere and the first chamber 27, the air leaves the chamber 27 and the channel 31 via the opening 41. In this way, as described above, the air is drawn into the hole 60 and out of the tubular portion 43 after the rotation of the shaft 15. These systems They are particularly useful in common household gaps, but they can also find applications in many other fields. Although the aforementioned design works well for many applications, there is still a current desire to increase efficiency in these devices. Particularly, it has been found that the nature of the air flow within the channel 31 leads to efficiency losses as described in the Background Art. To increase efficiency, an insert 80 is provided which directs the air flow after it leaves the fan 64. The insert 80 may be pre-installed on an engine / fan assembly, or due to its compact and simple design, may be installed in some way after its commercialization. Or, the insert 80 and the outer clamp 21 can be formed, with a
single piece and couple after an engine assembly and fan subassembly very similar to the separate components described here. Regardless of whether the insert 80 is provided as a separate piece or as a single integral piece of construction with external clamp 21, seal 48 or its equivalent is provided to ensure that moisture is kept away from the bearing 46. The insert 80 is generally shaped of the cup and includes a lining wall 81 which is disc-shaped and centered about the axis 15. The lining wall is centered around the axis 15. The lining wall is sized to be placed on and cover the inner plate 28 when it is Install A tapered projection 82 is provided which is raised to allow the projection 47 to be placed underneath. The tapered projection 82 projects from the concentric center of the facing wall 81 towards the fan 64 e. it includes an orifice 83 which allows the shaft 15 to project through it. The front facing wall 81 also includes a plurality of counterbored holes 84 each of which is adapted to receive the screw 52 therethrough. When mounted, the threaded portion of the screw 52 projects through the wall 81 and into the holes 51
provided in the internal plate 28. In addition, the head of the screw 52 is received in the reaming of the holes 84 so that no part of the screw extends above the surface of the front facing wall 81. In this way, a once the screws 52 are tightened, the insert 80 is secured to the end clamp 21. The cladding wall 81 terminates in a circumferential ridge 85 which extends axially inwardly from the radial edge of the cladding wall 81 towards the clamp 21. The flange 85 is sized to be placed around the inner flange, 29. Positioned on the radially outward surface of the circumferential flange 85 is a ramp 86. The ramp 86 is adapted to be received in the channel 31 and is configured to define a depth that gradually changes circumferentially. Up to that point, the ramp 86 includes an angled wall 87 which extends radially from the ridge 85 towards the external rim 24 of the external clamp 21. The angled wall 87 is positioned at an angle relative to the bottom surface 32, of so that as the angled wall 87 is wound around the lining wall 81 it defines an upper end 88 and a lower end 89. Said
another way, the angled wall 87 is helically deposited around the facing wall 81. The upper end 88 is positioned relatively further from a lower surface 32 of the channel 31 as compared to the lower end 89 which is closer to the lower surface 32. In the present embodiment, the lower end 89 is almost level with the lower surface 32. It should be appreciated that, although the present embodiment describes an angled wall 87 having a constant angle relative to the lower surface 32, it is description is not limited to those modalities. Specifically, the relative angle can vary circumferentially in a linear or logarithmic manner. The angled wall 87 is further supported by a pair of legs which terminate in the channel 31. Specifically, an inner leg 90 is positioned on the inner radial edge of the angled wall 87 and extends axially towards the bottom surface of the channel 31. Further, an outer leg 91 is placed on the radially outer edge of the angled wall 87 and extends axially towards the lower surface 32 of the channel 31. Each leg is provided with radial ends 92, which are adapted to be generally coupled to the radial corners 33 of the channel 31. As is evident from Figure 6, the height of the legs 90 and 91
It varies circumferentially. Specifically, when the angled wall 87 is positioned closer to the bottom surface, the legs 90 and 91 are correspondingly shorter, in the same way, when the angled wall 87 is located further away from the bottom surface 32, the legs 90 and 91 are correspondingly shorter. legs 90 and 91 are relatively longer. Positioned near the upper end 88 is a terminal wall 93, which extends downward from the angled wall 87 to the lower surface 32 of the channel 31. When properly aligned, the terminal wall 93 can be placed at a generally parallel angle. with the horn 42. In order to properly align or maintain the proper position of the insert 80, the outer legs 91 include a plurality of slots 94 which are adapted to slidably receive the tabs 50 of the end bracket 21. When it is inserted thus, the Insert 80 can be indexed and oriented appropriately. Finally, the insert 80 includes a projection 95 which extends a distance along the radially outer edge of the angular wall 87, which starts at the upper end 88 and extends circumferentially. The projection 95 restricts the cross section of the upper end of the ramp.
This helps to control the deceleration of the air leaving the fan 64 and also introduces more air into the bottom of the ramp so that it comes out through the horn 42, rather than continuing the cycle through the cover. As evident from Figure 5, the tapered ramp 86 does not extend around the entire circumference of the channel 31. When properly installed, this interruption in the tapered ramp 86 aligns with the interruption in the channel 31 defined by the opening 41 In other words, the terminal wall 93 is positioned near a first end 108 of the opening 41 and the lower end 89 of the angled wall 87 is positioned near a second end 109. In this manner, the insert 180 is secured to this mode to the end clamp 21, and when properly positioned, changes the profile and cross-sectional area of the channel 31 as a function of the circumferential position. When the shaft 15 is rotating, thus operating the working air fan 64, the air that is driven from the vanes 65 is more efficiently directed to the opening 41 on the end clamp 21. Specifically, when installed as shown in the present embodiment, in the counter-clockwise direction the effective cross-sectional area of the channel 31 is gradually increased
starting at the upper end 88. The effective cross-sectional area of the channel 31 is at its maximum in the interrupted portion of the insert 80 corresponding to the opening 41. By varying the cross section in that manner, the kinetic energy stored in the air in motion it can be converted more completely into static pressure rather than heat-induced turbulence, due to the reduction of parasitic currents when the air leaves the rotating fan. On the basis of the foregoing, the advantages of the constructions described above are readily apparent. In particular, the insert 80 is configured to provide a more efficient path for air to travel within the sub-assembly of the fan 12. When the insert 80 is installed the efficiency of the fan is increased, thus requiring less energy to provide the same air flow. In addition, the insert 80 is configured to be easily installed in pre-existing fan subassembly designs and can be used in single or multi-stage devices (as shown in the present embodiment). In this way, the invention described represents a great improvement in the technique of fan assemblies. In this way, it can be observed that the objectives
of the invention have been satisfied by the structure presented above. Although according to the patent statutes, only the best mode and preferred modalities have been presented and described in detail, it should therefore be understood that the invention is not limited thereto, therefore. Accordingly, for an application of the aspect and scope of the invention, reference should be made to the following claims.