Hollow Rotor Shaft Cooling Medium Distribution Element
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Solution Overview
Problem
Existing electrical machine rotors face inefficiencies in cooling due to uneven distribution of cooling mediums, leading to inadequate heat dissipation and increased weight from excessive coolant use, which compromises performance and efficiency.
Innovation Solution
A hollow rotor shaft design with a symmetrical coolant distribution element that directs the cooling medium radially along the inner surface of the cylinder jacket, utilizing centrifugal force for efficient distribution and minimizing the amount of coolant needed, thus achieving uniform cooling without excessive weight or structural complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the hollow cylinder is almost completely filled with coolant to achieve large heat transfer surface area, then cooling efficiency is improved, but the moving mass increases significantly
Solution Approach 1:
The cooling medium distribution element creates local cooling zones at specific positions along the inner surface of the cylinder jacket, rather than requiring uniform filling of the entire hollow cylinder. This allows effective cooling to be achieved with minimal coolant volume, thus reducing moving mass while maintaining cooling efficiency.
Solution Approach 2:
Instead of completely filling the hollow cylinder with coolant, the invention uses partial action by introducing coolant only to the extent necessary for effective heat transfer. The distribution element ensures this partial coolant volume is utilized optimally to cool the rotor shaft without the penalty of excessive moving mass.
2Volume of moving object
If small cross sections are selected for coolant lines to reduce volume requirement, then volume is reduced, but the coolant can only wet small areas and large-area distribution is not achieved
Solution Approach 1:
The cooling medium distribution element transforms the one-dimensional flow path into a two-dimensional distribution pattern by radially directing coolant onto the inner surface of the cylinder jacket. This dimensional transition allows a small coolant volume to cover a large surface area, resolving the contradiction between minimal coolant volume and maximal cooling surface area.
Solution Approach 2:
The cooling medium distribution element acts as an intermediary between the coolant supply and the rotor shaft surface. It receives a small volume of coolant and distributes it over a large area through its radial discharge structure, enabling efficient heat transfer without requiring large coolant volumes or complex line systems.
3Ease of operation
If forced guidance of coolant through channels or bores is implemented, then coolant can be directed to specific areas, but high pressure loss occurs due to flow resistance
Solution Approach 1:
The invention extracts the coolant from confined channels or bores and releases it directly into the hollow cylinder cavity. This eliminates the need for complex forced guidance systems with multiple channels, significantly reducing flow resistance and pressure loss while maintaining the ability to direct coolant to the rotor shaft surface for effective cooling.
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 design enhances the rotor's cooling efficiency, reduces the mass of the rotating components, and increases the power-to-weight ratio, allowing for a lightweight construction with minimal additional components and energy consumption, while maintaining optimal heat dissipation.
Implementation Method 1
A hollow rotor shaft design with a symmetrical coolant distribution element that directs the cooling medium radially along the inner surface of the cylinder jacket, utilizing centrifugal force for efficient distribution
Implementation Method 2
Existing electrical machine rotors face inefficiencies in cooling due to uneven distribution of cooling mediums, leading to inadequate heat dissipation
Data Source
Figure 1~2
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AI summary
The invention relates to an assembled hollow rotor shaft for a rotor of an electric machine, which rotor rotates about a longitudinal axis, said hollow rotor shaft comprising a cylindrical shell, which surrounds a shaft cavity, and end flanges arranged on both ends of the cylindrical shell, wherein a shaft journal is located on each end flange and wherein an inlet is provided in one of the end flanges, in particular in the shaft journal thereof, via which inlet a cooling medium can be conducted into the shaft cavity and to an inner surface of the cylindrical shell, wherein a cooling-medium distribution element that is symmetrical perpendicularly to the longitudinal axis is arranged inside the shaft cavity, which cooling-medium distribution element receives the cooling medium entering via the inlet by means of a receiving region, conducts said cooling medium toward the inner surface of the cylindrical shell by means of conducting-away region, and discharges said cooling medium onto the inner surface by means of a discharge region. The invention further relates to a rotor having a hollow rotor shaft according to the type indicated above, which hollow rotor shaft is fitted with laminated cores, and to an electric machine having a rotor of the type indicated above.