Integrated Fan Speed Multiplication in Dynamo-Electric Machines
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Solution Overview
Problem
Dynamo-electric machines with a large number of poles, characterized by slowly rotating rotors, often experience insufficient coolant throughput due to the inherent fan's rotation, necessitating additional forced ventilation, which increases complexity and costs.
Innovation Solution
A dynamo-electric machine with a friction wheel planetary gear connected to the fan hub, which increases the fan speed by a factor of two, enhancing air throughput without requiring additional axial space or external ventilation, utilizing standard bearings with a modified driver bushing to transmit shaft speed to the rolling elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the fan is directly connected to the shaft, then the structure is simple, but the fan speed is insufficient for adequate cooling in high-pole machines
Solution Approach 1:
A friction wheel planetary gear is introduced as an intermediary mechanism between the shaft and the fan. The gear includes a driver bushing that transmits shaft speed to rolling elements, which then drive the fan through friction contact. This intermediary gear system enables speed multiplication while maintaining a compact integrated structure within the fan hub.
2Temperature
If additional forced ventilation is provided, then adequate cooling is achieved, but technical complexity and production costs increase
Solution Approach 1:
The inherent fan is modified to serve itself by integrating a friction wheel planetary gear directly into the fan hub. The gear uses standard roller bearings with a modified driver bushing that transmits rotational speed from the shaft to the fan through the rolling elements. This self-contained speed multiplication system eliminates the need for external forced ventilation devices while maintaining adequate cooling.
3Speed
If a planetary friction gear is used to increase fan speed, then cooling performance improves, but axial space requirements increase
Solution Approach 1:
The planetary friction gear is nested within the fan hub structure itself. The driver bushing is integrated into the hub, and the rolling elements are contained within the hub's radial and axial dimensions. This nesting approach allows the speed multiplication mechanism to occupy minimal additional axial space while achieving the required fan speed increase.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures adequate cooling for high-pole dynamo-electric machines by nearly doubling the fan speed, resulting in eight times higher fan performance and sufficient air throughput at lower shaft speeds, eliminating the need for external ventilation and maintaining a fail-safe design using tried-and-tested standard parts.
Implementation Method 1
the speed of the shaft is transmitted to the rolling elements of a bearing via the driving bush
Implementation Method 2
Two roller bearings of different diameters, a drive shaft on which the inner races of the two roller bearings are pressed against each other axially
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a dynamo-electric machine, in particular a multi-pole dynamo-electric machine, that comprises a shaft (2) and an integrated ventilator which is connected to said shaft (2) by means of a friction-wheel planetary gear.