Rotating Electric Machine Coolant Flow Regulation
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Solution Overview
Problem
Existing rotating electric machines with liquid coolants suffer from increased agitation loss and inefficient cooling of coil end portions due to shearing forces and poor coolant distribution, leading to reduced cooling efficiency and increased thermal resistance.
Innovation Solution
Incorporation of flow direction regulating members that axially face the rotor, creating a Venturi effect to direct coolant flow and reduce shearing losses, while ensuring effective coolant distribution to coil end portions by regulating the flow direction and amount within the annular gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the rotor rotates at high speed, then the cooling effect on the stator core is improved, but the agitation loss of the liquid coolant increases due to shearing force
Solution Approach 1:
The patent divides the liquid coolant flow path into multiple regions: a first liquid coolant flow path for cooling the stator core and a second liquid coolant flow path for cooling the coil end portions. This segmentation allows different flow characteristics and cooling strategies for different components, reducing overall agitation loss while maintaining effective cooling.
Solution Approach 2:
The patent applies different cooling approaches to different locations: the stator core receives coolant through the annular gap with controlled flow, while the coil end portions receive coolant through dedicated cooling members. This local differentiation optimizes cooling efficiency while minimizing energy loss from shearing forces in each specific region.
2Temperature
If the liquid coolant flows into the annular gap between stator and rotor, then the stator core is cooled effectively, but shearing force loss occurs due to rotor rotation
Solution Approach 1:
The patent separates the coolant flow into a first flow path through the annular gap for stator core cooling and a second flow path through cooling members for coil end cooling. This segmentation reduces shearing loss by controlling coolant interaction with the rotating rotor while maintaining effective stator cooling.
Solution Approach 2:
The patent introduces cooling members as intermediary structures that deliver coolant to the coil end portions without requiring direct contact between the liquid coolant and the high-speed rotating rotor, thereby reducing shearing force loss while maintaining cooling effectiveness.
3Temperature
If the liquid coolant is agitated by the rotor, then the coil end portions are cooled, but part of the coolant does not reach the cooling targets and directly reaches the case
Solution Approach 1:
The patent uses cooling members as intermediaries to guide and direct the liquid coolant flow toward the coil end portions. These cooling members ensure that the coolant reaches the intended cooling targets effectively, preventing direct contact with the case and improving overall cooling efficiency.
Solution Approach 2:
The patent implements targeted cooling by directing coolant through specific paths: the first path cools the stator core through the annular gap, while the second path delivers coolant to the coil end portions through cooling members. This localized approach ensures coolant reaches the correct cooling targets, improving productivity and cooling efficiency.
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
Significantly reduces coolant shearing losses and enhances cooling efficiency by effectively directing coolant to coil end portions, thereby minimizing thermal resistance and maintaining effective cooling even at higher rotational speeds.
Implementation Method 1
Consequently, negative pressure is created by the Venturi effect, causing the coolant, which has flowed into at least part of the annular gap between the radially inner peripheral surface of the stator and the radially outer peripheral surface of the rotor, to be discharged radially outward.
Implementation Method 2
Moreover, with rotation of the rotor, the coolant in the axial gap is discharged by the centrifugal force of the rotor radially outward.
Data Source
AI summary
A rotating electric machine includes a rotating shaft, a rotor fixed on the rotating shaft, a stator, a housing, a liquid coolant and a flow direction regulating member. The stator is arranged so that a radially inner peripheral surface of the stator radially faces a radially outer peripheral surface of the rotor through an annular gap formed therebetween. The housing covers both axial ends of the stator and rotatably supports the rotating shaft. The liquid coolant is provided in an internal space formed in the housing to flow into at least part of the annular gap formed between the radially inner peripheral surface of the stator and the radially outer peripheral surface of the rotor. The flow direction regulating member axially faces an axial end face of the rotor through an axial gap formed therebetween and regulates the flow direction of the coolant by means of the axial gap.