Rotor Winding Ventilation Channels for Cooling Air Inlet
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Solution Overview
Problem
Conventional rotary-electric machine rotors experience inadequate cooling performance due to inefficient introduction of cooling air into ventilation channels, leading to temperature rises in the rotor winding, especially when the air inlet angle is not parallel to the axial direction, resulting in reduced cooling efficiency.
Innovation Solution
The rotor design incorporates ventilation channels in the conductors with air inlet holes at the bottom of the conductors opposite to the channel side, allowing cooling air to enter regardless of the air inlet angle, and exhaust holes that ensure effective airflow through the channels, improving airflow distribution and reducing temperature rises.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If air inlet holes are disposed in the side surface of the conductor, then the structure is simple, but the cooling performance is insufficient when the air inlet angle is not parallel to the axial direction
Solution Approach 1:
The air inlet holes are repositioned from the side surface to the bottom surface of the conductors, changing the spatial dimension of the opening location. This dimensional change allows the air inlet holes to face the axial direction directly, enabling effective cooling air introduction regardless of the air inlet angle, thereby resolving the contradiction between manufacturing simplicity and cooling performance
Solution Approach 2:
Instead of having air inlet holes on the side surface that require the air to approach from a specific angle, the invention inverts the approach by placing holes in the bottom surface that face axially upward. This inversion allows cooling air to be introduced effectively even when the overall air inlet angle is not parallel to the axial direction, maintaining cooling performance while preserving manufacturing simplicity
2Temperature
If ventilation channels are formed in the conductors, then the cooling air can circulate through the conductors, but the temperature distribution in the longitudinal direction is uneven
Solution Approach 1:
The ventilation channel is divided into multiple sections along the longitudinal direction of the conductor, with each section having its own air inlet hole at the bottom. This segmentation allows cooling air to be introduced at multiple points along the length of the conductor, creating more uniform temperature distribution in the longitudinal direction while maintaining the benefits of internal ventilation channels
Solution Approach 2:
Different portions of the conductor receive cooling air through locally positioned air inlet holes at the bottom surface. Each local region has its own air inlet opening that faces the axial direction, providing targeted cooling to specific sections and ensuring uniform temperature distribution throughout the longitudinal direction
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 cooling performance of the rotor winding by ensuring efficient airflow and reducing temperature rises, even at high rotational speeds, without significant structural changes.
Implementation Method 1
ventilation channels which are formed in the surfaces of the conductors along a longitudinal direction and through which cooling air flows
Implementation Method 2
air inlet holes which introduce the cooling air
Data Source
Figure 1~3
Figure 4~5
Figure 6
AI summary
In a rotor of a rotary-electric machine, in order to improve a cooling performance of a rotor winding, in a rotor winding on an end portion of the rotor (4) in an axial direction, the rotor winding being held by a retaining ring (3) of the rotor winding formed by laminating a plurality of conductors (11-19) in slots (6) of a rotor iron core (4a) extending in an axial direction and having a plurality of slots (6) formed at predetermined intervals in a peripheral direction, ventilation channels (41-49) through which cooling air (9) flows are formed in the surfaces of the conductors (11-19) along a longitudinal direction. The ventilation channels (41-49) have air inlet holes (21-29) which guide the cooling air (9) and exhaust holes (51-59) which exhaust the cooling air (9), the conductors (11-19) provided with the ventilation channels (41-49) which are formed in the surfaces of the conductors (11-19) along the longitudinal direction and through which the cooling air (9) flows are laminated to constitute the rotor winding, and the conductors (11-19) include openings of the air inlet holes (21-29) in bottoms of the conductors (11-19) on a side opposite to a side on which the ventilation channels (41-49) are formed.