Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1991-07-26
1992-07-28
Stephan, Steven L.
Electrical generator or motor structure
Dynamoelectric
Rotary
310 58, H02K 900, H02K 906
Patent
active
051343290
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to an electrical machine with a vertical shaft and a fan secured on the rotor shaft below the rotor plate packet, centered on a hub and removable from the hub.
In known self-ventilated vertical electrical machines, a fan for circulating cooling air is customarily arranged below the electrically active parts of the rotor in such a way that the cooling air can be drawn in from above the machine with as few impurities as possible and be blown out in a bottom region of the machine. Further, it must be possible to lift the rotor upward out of the machine casing for maintenance purposes. This, however, requires first unscrewing the fan, which generally has a greater diameter than the rotor, and depositing it in the casing.
Usually, axially extending screws are used to fasten the fan on the hub. When reinstalling the rotor after maintenance, the fan must then again be centered on the hub, and the attachment holes in the fan and in the hub must register exactly in circumferential direction to be able to introduce the axial screws. This may present difficulties for machines of relatively great power because vision onto the location of the fan attachment is obstructed by the casing. Besides, the weight of the rotor of the electrical machine, as well as that of the fan, hinders the assembly operation.
SUMMARY OF THE INVENTION
The present invention overcomes these difficulties by providing a design of a centering detachable attachment of the fan on the hub of the rotor shaft in such a way that easy assembly or disassembly is possible.
To solve this problem, a vertical electrical machine of the initially described kind is designed according to the present invention in such a way that on an end face, away from the rotor plate packet, the hub of the fan has an annular projection to be gripped from behind in a radial direction. At at least three points evenly distributed over the circumference of the fan disk there are clamping pieces movable in the radial direction that can be brought into positive and frictional engagement on the annular projection. On the retention mechanism of each clamping piece at the fan disk, at least one stop is provided which limits the radial movement of the clamping piece inwardly.
Thus, a clamping connection is provided between the fan and the hub on the rotor shaft that is independent of the circumferential position of the fan disk relative to the hub. No additional imbalance is created due to the use of annular or evenly distributed parts.
In the vertical electrical machine designed according to the present invention, clamping pieces are provided in at least three points, evenly distributed along the inner circumference of the fan disk. The clamping pieces, through a movement directed radially outward, abut positively at a corresponding counterface, engageable from behind, of a projection at the fan hub. The abutment brings about the positive and frictional clamp union. The clamp union is released in a simple manner by an oppositely directed movement, radially inward. The movement of the clamping piece in the radial direction inward is limited by a stop, which during disassembly prevents the clamping piece from becoming detached from the attachment to the fan disk and falling into the machine casing. The stop permits the freedom of movement in the radial direction necessary for making and breaking the positive and frictional clamping. Since the projection on the fan hub that permits the positive engagement for the clamp union is annular, total independence from the circumferential position is achieved, so that rotation of the rotor relative to the fan, which remains in the casing, has no influence on their mutual attachment to each other.
The radial movement of the clamping piece for establishing the clamp union can best be brought about by a radially directed screw which traverses a threaded bore in the clamping piece and is retained at the fan disk. This screw also carries the stop, which lies at a distance before an inner wall
REFERENCES:
patent: 2286750 (1942-06-01), McMahan
patent: 4441042 (1984-04-01), Colwell
patent: 4564775 (1986-01-01), Mazzorana
patent: 4956572 (1990-09-01), Strobl
Search Report, dated Oct. 11, 1989, 5 pages.
Siemens Aktiengesellschaft
Stephan Steven L.
To E. H.
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