WO1999067535A1

WO1999067535A1 - Mounting of fan to motor drive shaft

Info

Publication number: WO1999067535A1
Application number: PCT/BR1998/000036
Authority: WO
Inventors: Juan Carlos Carne Correa
Original assignee: Springer Carrier S.A.
Priority date: 1998-06-22
Filing date: 1998-06-22
Publication date: 1999-12-29
Also published as: AU7900998A

Abstract

The combination of a motor drive shaft and a fan (36) to be rotatably driven by and axially affixed to the shaft. The drive shaft includes a longitudinally extending section having a substantially D-shaped cross section for at least a portion of the length. The D-shaped cross section defines a flat surface (74), which is provided with a depression (76) formed thereon extending transversely to the shaft. The fan (38) has a rotational axis and a central mounting hub (58) having an opening therethrough along the rotational axis. The opening has a D-shaped cross section including a flat surface, which is configured to receive and engage the section of the drive shaft having a D-shaped cross section in a manner to allow the shaft to rotationally drive the fan (38). The hub (58) is provided with a deformable shaft engaging structure formed integrally therewith and configured to cooperate with the depression (76) of the drive shaft to axially retain the fan with respect to the shaft when the deformable engaging structure is in an undeformed position. When the structure is deformed, it will allow axial movement of the fan with respect to the shaft to facilitate installation and removal of the fan.

Description

MOUNTING OF FAN TO MOTOR DRIVE SHAFT

Technical Field

The invention generally relates to air distribution units of the type commonly used in air conditioning, heating or ventilation systems, more particularly it relates to mounting of a fan which may be used in such systems. Background Art

In many commercial air conditioning, heating and ventilating systems, treated air is discharged into an area to be conditioned through an air distribution or conditioning unit. For example, one general type of air conditioning system, often referred to as a split system, includes separate indoor and outdoor units. The outdoor unit includes a compressor, a heat exchanger and a fan. The indoor unit includes a heat exchanger and a fan. In operation, the indoor fan draws air into the indoor unit, through an inlet thereof, and forces the air over the indoor heat exchanger and then out of the indoor unit, through an outlet opening therein.

The outdoor fan draws air into the outdoor unit, through an inlet, forces that air over the outdoor heat exchanger and then forces that air out of the outdoor unit through an outlet therein. At the same time, a compressor causes a refrigeration fluid to circulate through and between the indoor/outdoor heat exchangers. At the indoor heat exchanger, the refrigerant absorbs heat from the air passing over that heat exchanger, cooling that air. At the same time, at the outdoor heat exchanger, the air passing over the heat exchanger absorbs heat from the refrigerant passing therethrough.

A common arrangement for the indoor fan is a horizontally mounted motor having a drive shaft extending from one or both ends thereof and having a squirrel cage type centrifugal fan mounted to the shaft. Typically, the mounting of the fan to the shaft is achieved with mounting hardware which includes clips and/or threaded fasteners which must be installed and tightened manually in order to attach the fans to the motor shafts. Disclosure of the Invention

The combination of a motor drive shaft and a fan to be rotatably driven by and axially affixed to the shaft. The drive shaft includes a longitudinally extending section having a substantially D- shaped cross section for at least a portion of the length. The D-shaped cross section defines a flat surface, which is provided with a depression formed thereon extending transversely to the shaft. The fan has a rotational axis and a central mounting hub having an opening therethrough along the rotational axis. The opening has a D-shaped cross section including a flat surface, which is configured to receive and engage the section of the drive shaft having a D-shaped cross section in a manner to allow the shaft to rotationally drive the fan. The hub is provided with a deformable shaft engaging structure formed integrally therewith and configured to cooperate with the depression of the drive shaft to axially retain the fan with respect to the shaft when the deformable engaging structure is in an undeformed position. When the structure is deformed, it will allow axial movement of the fan with respect to the shaft to facilitate installation and removal of the fan. Brief Description of the Drawings

The invention may be better understood and its objects and advantages will become apparent to those skilled in the art by reference to the accompanying drawings, in which:

Figure 1 is a perspective view of the indoor unit of an air conditioner which embodies the features of the present invention; Figure 2 is an exploded view of the fan motor and centrifugal fans of the air conditioning unit of Figure 1 ;

Figure 3 illustrates the fan motor and fans of Figure 2 assembled to one another;

Figure 4 is a simplified partial sectional view of the assembly of Figure 3 illustrating the engagement of the fan motor shafts with the fans;

Figure 5 is an enlarged showing of the detail identified as Figure 5 in Figure 4;

Figure 6 is an enlarged showing of the detail identified as Figure 6 in Figure 4; and

Figure 7 is an exploded perspective view of the air conditioning unit of Figure 1. Best Mode For Carrying Out The Invention And Industrial Applicability

Looking first at Figures 1 and 7, the indoor unit 10 of a split system air conditioning system of the type incorporating a fan mounting according to the present invention is illustrated. Briefly, the unit 10 includes a main structural support frame 12, which includes a bottom panel 14, a back panel 16 and a top section 18. Attached to the sides of the back and top panels are structural internal side covers 20. The side covers 20 and the back panel 16 cooperate to support a horizontally extending fan support panel 22, which includes a pair of rectangular openings 24 formed therein. Mounted above the fan support panel 22 on a pair of inclined surfaces 26, defined by the internal side covers 20 is a heat exchanger coil 25.

Mounted under the top section of the main support frame 12 is an upper condensate collection pan 28. Mounted in the front of the unit, under the bottom of the heat exchanger 25, and supported by the front edge 30 of the fan support panel 22, is a lower condensate collection pan 32. A front section of the lower condensate collection pan extends upwardly and is spaced from the heat exchanger coil 25. Mounted to the lower surface of the fan support panel 22 is a fan assembly 34, which includes an electric motor 36 adapted to drive a pair of centrifugal fans 38, which are each enclosed in a two-piece scroll housing 40. Each of scroll housings 40 defines a rectangular upper air outlet opening 39, which is in air flow communication with the rectangular openings 24 in the fan support panel 22.

As a result of the above-described arrangement of components, when the fan assembly is energized, air is drawn into the region 41 underlying the fan support panel 22 through the open front and is directed upwardly through the rectangular openings 24, through the heat exchanger coil 25 and is discharged through an opening 42 defined by the upper edge 44 of the lower condensate pan 32 and the front edge 46 of the upper condensate pan 28.

Looking now at Figure 2, the electric motor 36 is a standard electrically actuated motor of the type used for air conditioning operation which has motor drive shaft sections extending from both ends of the motor. Both the left-hand drive shaft section 48 and the right-hand drive shaft section 50 are part of a continuous drive shaft and each includes a fan engaging conformation 52 and 54, respectively, formed thereon. It will be noted that a part of the conformations 52 and 54 are at different axial positions on the shafts 48 and 50. As will be seen, this allows the fan 38 and the fan shaft engaging structure of the fans to be identical regardless of whether the fan is mounted on the left or right-hand drive shaft.

The fans 38 are centrifugal fans having a central hub 58, which includes a circular radially outwardly extending divider section 60, which in turn supports two sets of longitudinally extending blades 62 and 64 extending from the outer periphery thereof 66 on the left and right-hand sides thereof, respectively. Each fan 38 accordingly has a large circular inlet opening 68 and 70 at the right and left-hand sides thereof to thereby define the flow path through the fan through the two inlets and outwardly through the two sets of blades 62 and 64. As best shown in Figures 2 and 4 - 6, the left-hand motor shaft

48 comprises a main shaft section 72 having a circular cross section and an axially extending flattened section 74 at the outer end thereof defining a substantially D-shaped cross section of the shaft in the region of the flat. A transversely extending slot or recess 76 is formed across the flattened portion 74 in close proximity to the outer end of the left-hand shaft 48.

The right-hand motor shaft 50 also includes a main shaft section and a flat as described above in connection with the left-hand shaft. It will be noted however that the recess 76 in the right-hand shaft is formed at the axial inner end of the flat section 74 of the shaft. The central hub 58 of the fans 38 defines a longitudinally extending cylindrical motor shaft receiving section 78, which has an axial opening 80 extending therethorugh having a D-shaped cross section defining a flat 82, which is configured to be received in a mating close tolerance fit with the D-shaped section of the motor shaft to which it is assembled. The left-hand side of the cylindrical shaft receiving section 78 is provided with a pair of axially extending slots 84 therein on opposite sides of the flat 82. The slots 84 isolate a longitudinally extending finger 86 of the cylindrical shaft receiving section 78. The finger is affixed to the cylindrical section 78 at a first end 88 thereof and the outer free end is provided with a downwardly extending protrusion 92, which is configured to be received in and engage the transverse recesses 76 formed in the flat section 74 of the motor drive shafts. The length of the slots 84 assure that the length of the finger 86 is such that it is able to flex radially outwardly when the shaft engages the outer flat 74 of the main shaft and to assure that it flexes inwardly to engage the protrusion 92 with the mating recess 76 when a fan is in the proper axial position with respect to a motor drive shaft.

As best seen in Figures 5 and 6, the fan hub 58 is further provided with a structural extension 94, which is positioned in overlying spaced relationship with the finger 86 by a distance represented by reference numeral 96. The distance 96 and the length of the structural extension 94 are determined so that the extension serves to limit the upward flexing of the finger 86 in order to prevent inadvertent breaking of the finger during installation or removal of a fan from a motor shaft. With references to Figures 4, 5 and 6, it will be seen that, because of the different axial locations of the recess 76 on the motor shafts 48 and 50, a single fan configuration, as described above, may be mounted to either motor shaft and the engagement of the protrusion 92 with the recess 76 of the appropriate shaft will result in correct axially positioning and retention of the fan with respect to the motor shafts.

Claims

What is claimed is:

1. The combination of a motor drive shaft and a fan to be rotatably driven by and axially affixed to said shaft; said drive shaft comprising a longitudinally extending section having an axis, said longitudinal section having a substantially D-shaped cross section for at least a portion of the length thereof, said D-shaped cross section defining a flat surface, said flat surface having a depression formed therein extending transversely to said axis; said fan having a rotational axis and a central mounting hub having an opening therethrough along said rotational axis, said opening having a D-shaped cross section, including a flat surface, configured to receive and engage said section of said shaft having a D-shaped cross section thereon in a manner to allow said shaft to rotationally drive said fan; said hub having a deformable shaft engaging structure formed integrally therewith configured to cooperate with said depression of said drive shaft to axially retain said fan with respect to said shaft when said deformable engaging structure is in an undeformed position, and to allow axial movement of said fan with respect to said axis when in a deformed position.

2. The apparatus of claim 1 wherein said deformable engaging structure comprises a flexible finger having one end thereof integrally formed with said hub, said finger including; a flexible elongated section extending from said one end thereof in a direction parallel to said flat surface; and a latching head formed at the other end thereof configured to engage said depression in said drive shaft.

3. The apparatus of claim 2 wherein said hub further includes a movement limiting stop integrally formed therewith, spaced radially outward from said deformable elongated section and extending substantially parallel thereto, the spacing of said stop being of a predetermined dimension to limit flexing deformation of said deformable engaging structure to prevent breakage when being deformed from said undeformed position.