Rotary Electric Machine Sealing Recess for Coolant Channel
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Solution Overview
Problem
In rotary electric machines, the sealing agent can extrude into the coolant channel during formation, leading to clogging and decreased cooling performance, and increasing the sealing agent's area facing the channel inhibits this but causes issues with screw fixation due to uncontrolled axial force from tightening torque.
Innovation Solution
A recess is provided between the screw hole and the channel groove on the heat transfer member and lid member, allowing the sealing agent to flow into the recess instead of the screw hole, preventing it from entering the coolant channel and allowing controlled axial force during lid member fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the area of the sealing agent facing the channel is increased to inhibit extrusion, then sealing reliability is improved, but the sealing agent is pressed and expanded to enter the screw hole when the lid member is fixed, causing uncontrolled axial force
Solution Approach 1:
The sealing agent application area is segmented into two distinct zones: a first area facing the channel groove with larger area for preventing extrusion, and a second area facing the screw hole with smaller area to prevent entry into the screw hole. This segmentation resolves the contradiction by allocating different area characteristics to different functional regions.
Solution Approach 2:
Different areas of the sealing agent are given different quality characteristics: the first area has a larger area to provide strong sealing against the channel groove, while the second area has a smaller area to prevent interference with the screw hole. This local differentiation allows the sealing agent to simultaneously achieve reliable sealing and controlled tightening.
2Reliability
If the sealing agent area is increased to prevent extrusion to the channel, then cooling performance is maintained, but the lid member cannot be firmly fixed with controlled axial force
Solution Approach 1:
The sealing agent application area is divided into a first area for cooling channel sealing and a second area for screw hole protection. This segmentation allows the cooling channel to be reliably sealed (maintaining cooling performance) while preventing sealing agent interference with the screw hole, enabling proper fixation strength with controlled axial force.
Solution Approach 2:
The sealing agent is applied with locally differentiated area characteristics: a larger first area to ensure cooling channel sealing and maintain cooling performance, and a smaller second area to prevent interference with screw fixation. This local quality differentiation resolves the contradiction between cooling performance and fixation strength.
3Reliability
If the sealing agent is applied to ensure hermetic sealing, then channel airtightness is achieved, but the sealing agent breaks under coolant pressure and flows into the coolant causing channel clogging
Solution Approach 1:
The sealing agent application is segmented into a first area facing the channel groove for hermetic sealing and a second area facing the screw hole with reduced area. This segmentation ensures channel airtightness through the first area while the limited second area prevents sealing agent breakage and subsequent channel clogging.
Solution Approach 2:
Different areas of the sealing agent are given different quality characteristics: the first area has sufficient area to ensure hermetic sealing and prevent channel clogging, while the second area has reduced area to minimize breakage risk. This local quality approach resolves the contradiction between airtightness and prevention of harmful effects.
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 configuration prevents the sealing agent from entering the screw hole, ensuring stable and hermetic sealing of the coolant channel, maintaining cooling performance and allowing controlled tightening torque for long-term operation.
Implementation Method 1
a sealing agent for filling a gap between the heat transfer member and the lid member along the periphery of the channel groove
Implementation Method 2
a coolant supply/discharge unit for supplying/discharging a coolant to/from a channel surrounded by the channel groove and the lid member
Implementation Method 3
a through hole provided at a portion of the lid member which faces the screw hole, and a screw screwed into the screw hole through the through hole
Data Source
AI summary
The rotary electric machine includes a motor unit, and an inverter unit having a power module, a field module, and a cooler. The cooler includes a heat transfer member having, on the one-side surface, a channel groove recessed toward the other side, a lid member, a sealing agent, and a coolant supply/discharge unit; and the lid member is fixed to the heat transfer member with a screw hole, a through hole, and a screw; and, at a position between the screw hole and the through hole, and the channel groove, a recess is provided on one or both of the one-side surface of the heat transfer member and the other-side surface of the lid member, and the sealing agent is applied on the side closer to the channel groove than the recess while no sealing agent is applied on the side closer to the screw hole than the recess.