Generator and fan
An improved generator fan serves to draw air into the generator through an inlet in the generator housing, pass the air through the rotor and stator, and direct the air out openings in the generator housing. The fan of the present invention includes a disc and at least one multi-directional blade extending from the disc. The multi-direction blade includes a leading segment extending from the disc between a first radius measured from the axis of rotation and a second radius, the leading segment including a leading edge extending from the disc at an angle of about ninety degrees from the disc, the leading segment extending from the disc with an increasing angle along the length of the leading segment; and a trailing segment extending from the disc between the second radius and a third radius measured from the axis of rotation, the third radius being greater than the second radius and the trailing segment extending from the disc with an angle having a rate of change different than the leading segment.
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The present invention relates to an improved generator and fan. More specifically, the invention provides a generator utilizing an improved rotor fan.
BACKGROUND OF THE INVENTIONWithout a generator, the electrical load of a vehicle would quickly drain a fully charged battery. In a vehicle, a generator producing alternating current (AC), known as an alternator, is often mounted at the front of the engine and is linked to the engine crankshaft pulley by a drive belt. When the engine turns the drive belt, the drive belt turns a shaft in the alternator, and current is generated. Current is produced in an alternator when a wire intercepts a magnetic field. In an alternator, it is the wire, in coiled form, that is held stationary and the magnetic field is turned so that the magnetic field passes through the wire. Thus, alternators include a stationary part, the stator, and a rotating part, the rotor.
The stator may include stationary coils or slotted pins or segments that surround a rotor. As the rotor is turned by the car engine, the alternating magnetic field created by the rotor is intercepted by the stationary coils, pins or segments, and current flows through the stator first in one direction, then in the other, resulting in alternating current. As the rotor is turned, air flow within the assembly will produce noise in the audible range that will emanate from the alternator assembly.
The rotor includes an electromagnet that is magnetized by current from the battery. The electromagnet may include slip rings, rotor windings, and north and south pole members surrounding the rotor windings. Current from the battery flows through the slip rings to the rotor windings. North and south pole members have pole claws shaped like interlocking teeth surrounding the rotor windings. The north and south pole members create an alternating magnetic field as the rotor turns.
A housing surrounds the rotor and stator assembly. The stator is fixed relative to the housing and the rotor shaft is rotatably mounted relative to the housing. Because the battery and electrical components in the car work on direct current (DC), the AC output of the alternator must be converted to DC. This is done with rectifiers which pass current in one direction only. The components within the alternator produce heat and, in addition, the alternator operates under high under hood temperatures. To reduce the amount of heat in the alternator, a fan is included in the alternator assembly as seen in reference to U.S. Pat. No. 4,549,103 to Shega, entitled Multi-Path Cooling in an AC Generator for a Vehicle.
The fan may be placed inside or outside of the housing to increase airflow between the rotor and stator and to increase airflow through openings in the housing. The fan blades may face inward toward the central portion of the alternator or outward away from the central portion of the alternator. Rotation of the fan helps increase airflow within the alternator and helps to reduce heat within the alternator, but also increases the amount of audible noise emanating from the alternator assembly, an undesirable feature particularly from the point of view of the operator of the vehicle in which the alternator is mounted.
The noise produced by an alternator depends, at least in part, on the design of the alternator fan blades. Alternator fans with straight fan blades having an inside angle of more than ninety degrees from the base of the fan, tend to produce less noise, but undesirably also provide less airflow. Alternator fans with straight fan blades at ninety degrees from the base of the fan produce more airflow, but undesirably more noise. To improve the airflow resulting from a fan with swept out blades, the length of the blade can be increased but this undesirably reduces the number of blades that can be included on a single fan. Other designs have incorporated alternating blades, some blades at ninety degrees and other blades having an inside angle of more than ninety degrees. However, the limitations associated with each type of blade are not entirely overcome by known designs. The present invention overcomes these problems to provide an alternator incorporating an improved fan, resulting in an alternator with reduced noise, improved tonality and improved radial and axial cooling airflow.
SUMMARY OF INVENTIONThe present invention provides an improved generator with improved sound quality and reduced noise level, and also provides improved airflow through the generator, improving cooling of the generator components. An improved generator fan serves to draw air into the generator through an inlet in the generator housing, pass the air through the rotor and stator, and direct the air out openings in the generator housing. The fan of the present invention includes a disc adapted to be centrally mounted on a shaft that represents an axis about which the fan rotates. According to the present invention, at least one multi-directional blade extends from the disc. The multi-direction blade includes a leading segment extending from the disc between a first radius measured from the axis of rotation and a second radius measured from the axis of rotation, the leading segment including a leading edge extending from the disc at an angle of about ninety degrees from the disc, the leading segment extending from the disc with a swept out shape starting at the leading edge and extending from the disc with an increasing angle along the length of the leading segment. A trailing segment extends from the disc between the second radius and a third radius measured from the axis of rotation, the third radius being greater than the second radius and the trailing segment extending from the disc with an angle having a rate of change different than the leading segment.
An improved generator having the inventive fan exhibits improved tonality and a reduced noise level. The resulting generator also provides improved cooling. Other aspects of the present invention are provided with reference to the figures and detailed description of embodiments provided herein.
BRIEF DESCRIPTION OF THE DRAWINGSThe present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
The present invention provides a generator with improved sound quality and reduced noise level, and also provides improved airflow through the generator, improving cooling of the generator components. An improved generator fan serves to draw air into the generator through an inlet in the generator housing, pass the air through the rotor and stator, and direct the air out openings in the generator housing.
According to the embodiment shown in
According to one embodiment, the upper portion 210 of the multi-directional blade 170 terminates in an outer edge 230 defined by the outermost portion of the leading segment 180 and trailing segment 190, gradually increases in distance from the disc 120 as the leading segment 180 extends from the first radius 140 to the second radius 150 and gradually decreases in distance from the disc 120 as the trailing segment 190 extends from the second radius 150 to the third radius 160.
According to one embodiment, the leading section 180 sweeps from the angle of about ninety degrees at the leading edge to an angle of about one hundred twenty degrees where the leading segment 180 meets the trailing segment 190. This improves the flow rate in both the axial and radial direction by increasing the mount of air drawn in by the fan 110 while reducing noise level. According to one embodiment, the trailing segment extends from the disc 120 at an angle of about one hundred twenty degrees to provide the desired ratio of radial flow and axial flow of air to cool the generator. According to one embodiment, the trailing segment 190 extends from the disc at an angle greater than about one hundred twenty degrees, increasing the amount of axial airflow through the generator.
In this embodiment, the multi-directional blade 170′ is combined with at least one straight blade 240′ having a substantially planar shape and a straight interface 250′ with the disc 120′. The straight blade 240′ has a uniform angle from the disc 120′ along the entire length of the blade. Thus, the amount of radial and axial flow can be further adjusted by tailoring the angle of the straight blade 240′ to provide the desired amount in combination with the affect of the multi-directional blade 170′. The straight blade 240′ may be defined by a straight angle of ninety degrees, less than ninety degrees, or more than ninety degrees. Further, various combinations of straight and tilted blades may be incorporated into the improved fan 110′.
According to one embodiment, at least one flow port 260′ is included in the fan 110′ between the multi-directional blade 170′ and an adjacent blade. This improves airflow on both sides of the fan 110′. According to one embodiment, the fan 110′ includes six multi-directional blades 170′ and four uniform blades.
According to one embodiment, the leading section 180′ sweeps from the angle of about ninety degrees at the leading edge to an angle of about one hundred twenty degrees where the leading segment 180′ meets the trailing segment 190′. This improves the flow rate in both the axial and radial direction by increasing the mount of air drawn in by the fan 110′ while reducing noise level. According to one embodiment, the trailing segment extends from the disc 120′ at an angle of about one hundred twenty degrees to provide the desired ratio of radial flow and axial flow of air to cool the generator. According to one embodiment, the trailing segment 190′ extends from the disc at an angle greater than about one hundred twenty degrees, increasing the amount of axial airflow through the generator.
In the embodiment of
The improved fan described herein can be mounted axially inward of the housing with the blades extending outward. In an alternative embodiment, the fan can be mounted axially outward of the housing with the blades extending axially inward. More than one fan 110 may be employed in a single generator.
The invention provided herein allows more flexibility to tune a fan 110 design to provide airflow for a given application according to the desired noise level, tonality, axial airflow and radial airflow. While the present invention has been described with reference to exemplary embodiments, a variety of embodiments may be produced utilizing the apparatus and process described herein. Modifications and variations in the invention will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims and their equivalents will embrace any such alternatives, modifications and variations as falling within the scope of the present invention.
Claims
1. A generator fan, comprising:
- a disc adapted to be centrally mounted perpendicular to an axis of rotation and at least two multi-directional blades extending from the disc, the multi-directional blades including:
- a leading segment extending from the disc between a first radius measured from the axis of rotation and a second radius measured from the axis of rotation, the leading segment including a leading edge extending from the disc at an angle of about ninety degrees from the disc, the leading segment extending from the disc with a swept out shape starting at the leading edge and extending from the disc with an increasing angle along the length of the leading segment; and
- a trailing segment extending from the disc between the second radius and a third radius measured from the axis of rotation, the third radius being greater than the second radius and the trailing segment extending from the disc with an angle having a rate of change different than the leading segment;
- wherein said multi-directional blades further include an arced interface with said disc; and
- wherein said multi-directional blades overlap one another so that the leading segment begins proximal the second radius of an adjacent multi-directional blade.
2. A generator comprising:
- a generator shaft defining an axis of rotation;
- a fan including a disc mounted on the shaft and at least one multi-directional blade extending from the disc, the multi-directional blade including:
- a leading segment extending from the disc between a first radius measured from the axis of rotation and a second radius measured from the axis of rotation, the leading segment including a leading edge extending from the disc at an angle of about ninety degrees from the disc, the leading segment extending from the disc with a swept out shape starting at the leading edge and extending from the disc with an increasing angle along the length of the leading segment;
- a trailing segment extending from the disc between the second radius and a third radius measured from the axis of rotation, the third radius being greater than the second radius and the trailing segment extending from the disc with an angle having a rate of change different than the leading segment;
- at least one uniform blade having a uniform angle from the disc; and
- a flow port between said multi-directional blade and an adjacent blade.
Type: Application
Filed: Oct 4, 2004
Publication Date: Feb 24, 2005
Applicant:
Inventors: Duane Buening (Anderson, IN), Michael Hull (Anderson, IN)
Application Number: 10/958,019