Patent Application
20100283334
The present disclosure relates to a generator, and more particularly to an internal oil management system for a starter-generator.
Aircraft powered by gas turbine engines often include a mechanically driven accessory gearbox which connects to accessory systems such as an electrical starter-generator or electric generator.
High power density aircraft generators utilize an internal oil management system. The internal oil management system provides supplemental cooling to the generator main stator through a back iron oil flow which is defined by oil grooves formed within the stator housing. As the main stator is typically constructed as a stack of adhesively bonded laminations, a main stator sleeve is typically mounted between the lamination stack and the oil cooling grooves to ensure oil does not leak through the lamination stack into the generator air gap thus increasing generator losses due to viscous shear of oil within the generator air gap.
The main stator sleeve is typically constructed from bar or tube stock which is machined on an inner diameter to closely fit onto the main stator core. The outer diameter of the main stator sleeve is then machined after installation onto the main stator core to assure a close fit with the oil grooves. Although effective, such machining is relatively significant as machining is required prior and subsequent to main stator core assembly.
A main stator sleeve for a generator according to an exemplary aspect of the present disclosure includes a sheet of material that includes an arcuate notch on two opposed edges such that a butt joint therebetween defines a pin aperture.
A housing assembly for a generator according to an exemplary aspect of the present disclosure includes a cylindrical stator housing which defines at least one oil groove. A main stator sleeve mounted adjacent to the cylindrical stator housing to at least partially enclose the at least one oil groove and defines a butt joint.
A generator according to an exemplary aspect of the present disclosure includes a cylindrical stator housing which defines at least one oil groove. A main stator assembly is installed within the cylindrical stator housing such that a main stator sleeve is mounted between the cylindrical stator housing and the main stator assembly. The main stator sleeve at least encloses the at least one oil groove.
A method of forming a main stator assembly according to an exemplary aspect of the present disclosure includes locating a main stator sleeve formed from a rectilinear piece of material within a cylindrical stator housing which defines at least one oil groove and at least partially enclose the at least one oil groove.
Various features will become apparent to those skilled in the art from the following detailed description of the disclosed non-limiting embodiment. The drawings that accompany the detailed description can be briefly described as follows:
The dynamoelectric portion 22 in the disclosed, non-limiting embodiment is a 3-phase machine that includes three machines 30, 32 and 34 mounted on a common rotor shaft 36 along an axis of rotation A. Stator assemblies 30B, 32B, 34B of the three machines are installed in the main housing 28 and the three rotor assemblies 30A, 32A, 34A are installed on the rotor shaft 36. The main housing assembly 28 may be closed with a drive end (DE) cover assembly 28A through which the rotor shaft 36 extends and a non-drive end (NDE) cover assembly 28B.
The first machine 30 includes a permanent magnet generator (PMG) with a PMG rotor assembly 30A and PMG stator assembly 30B. The PMG stator assembly 30B supplies power for generator excitation, as well as power for other components of the electrical system. The second machine 32 includes a Main Exciter (ME) with a ME rotor assembly 32A and a stator assembly 32B. The ME receives field excitation from the PMG through a GGPCU (Generator and Ground Power Control Unit). The output of the ME rotor assembly 32A is supplied to a shaft mounted diode system 38. The diode pack 38 may be divided into six diode groups to provide a 3-phase full wave bridge rectification. The DC output of the diode pack 38 supplies the third machine 34.
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The main stator sleeve 56 includes an arcuate notch 60A, 60B on each opposed edge. The arcuate notch 60A, 60B are formed on the short ends of the rectilinear sheet in the disclosed embodiment, but the arcuate notch 60A, 60B may be formed on the long ends dependant on the cylindrical stator housing 52 configuration. The arcuate notch 60A, 60B forms a pin aperture 62 which receives the pin 58 (
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The main stator sleeve 56 is mounted within the cylindrical stator housing 52 such that the sleeve butt joint (
The main stator sleeve 56 readily facilities a reduction in generator cost via reduced sleeve piece part cost and reduced assembly/post assembly sleeve machining costs.
It should be appreciated that the sleeve of the present application is not limited to use in conjunction with a specific type of rotating machine. Thus, although the present application is, for convenience of explanation, depicted and described as being implemented in a starter-generator, it should be appreciated that it can be implemented in numerous other machines including, but not limited to, an auxiliary power unit, a turbo charger, a super charger, an air cycle machine, an alternator, an electric motor, an electric generator, an integrated constant speed drive generator and gearboxes of various types.
It should be understood that relative positional terms such as “forward,” “aft,” “upper,” “lower,” “above,” “below,” and the like are with reference to the normal operational attitude of the vehicle and should not be considered otherwise limiting.
It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should also be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit herefrom.
Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present disclosure.
The foregoing description is exemplary rather than defined by the limitations within. Various non-limiting embodiments are disclosed herein, however, one of ordinary skill in the art would recognize that various modifications and variations in light of the above teachings will fall within the scope of the appended claims. It is therefore to be understood that within the scope of the appended claims, the disclosure may be practiced other than as specifically described. For that reason the appended claims should be studied to determine true scope and content.
