Flexible Seal Plate for Starter Motor Bearing Box
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Solution Overview
Problem
Existing starter motors face challenges in reliably and cost-effectively sealing the bearing box due to the use of rubber or soft resin bearing covers, which are prone to detachment from heat and vibration, and require complex manufacturing processes, increasing costs and axial length.
Innovation Solution
A starter motor design featuring a flexible seal plate attached to the end face of the end frame to hermetically seal the bearing box, made from a laminate of thin aluminum sheet and polyester film, providing improved sealing performance and reduced manufacturing costs with a simpler production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubber or soft resin bearing cover is used to seal the bearing box, then the sealing function is provided, but the dimension control becomes difficult and manufacturing cost increases
Solution Approach 1:
The invention changes the material parameter from rubber/soft resin to metal plate, which fundamentally alters the dimensional stability and control characteristics. The metal seal plate provides precise dimensional control while maintaining sealing functionality through proper material selection and design.
Solution Approach 2:
The invention uses a laminate composite structure combining thin aluminum sheet and polyester film. This composite material provides both the dimensional stability of metal and the flexibility/sealing capability of polymer materials, resolving the contradiction between dimension control and sealing function.
2Reliability
If a rubber or soft resin bearing cover with annular projections is used, then sealing is achieved, but the shape becomes complicated and manufacturing cost increases
Solution Approach 1:
The invention extracts and eliminates the complex annular projection structure from the seal plate. Instead of adding protrusions, the patent uses a flat seal plate with sealing achieved through material flexibility and proper mounting, significantly simplifying the geometry and manufacturing process.
Solution Approach 2:
The invention changes the sealing mechanism from mechanical interlocking (projections) to material-based sealing (flexible plate conforming to the bearing box opening). This parameter change from structural complexity to material property utilization simplifies the overall design.
3Ease of manufacture
If a bearing cover is press-fit with small pressure, then assembly is simple, but sealing performance decreases under heat and vibration
Solution Approach 1:
The laminate composite of aluminum sheet and polyester film provides both the structural integrity for secure mounting and the flexibility for reliable sealing. The polyester film layer specifically provides the conformability needed to maintain sealing under thermal expansion and vibration while the aluminum provides structural stability.
Solution Approach 2:
The flexible seal plate can conform to slight curvatures and irregularities in the bearing box opening, creating a reliable seal through surface conformity rather than rigid mechanical interlocking. This allows simple press-fit assembly while maintaining sealing performance under various operating conditions.
4Reliability
If multiple annular projections are provided to block foreign matter, then sealing reliability improves, but the axial length of the bearing box increases
Solution Approach 1:
The invention completely removes the multiple annular projection structure that extended axially. Instead, a single flat seal plate provides foreign matter blocking through its planar barrier, reducing the axial length requirement while maintaining or improving sealing effectiveness.
Solution Approach 2:
The invention shifts the sealing approach from axial dimension (multiple stacked projections) to radial/dimensional plane (single flat plate). This dimensional transformation blocks foreign matter effectively while minimizing axial length occupation.
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
The flexible seal plate ensures reliable sealing against heat and vibration, reduces manufacturing costs, and minimizes the axial length of the starter motor, while allowing for easy diagnosis of faults through temperature-indicating adhesives or paint.
Implementation Method 1
a flexible seal plate that is attached on the end face of the end frame to hermetically seal the open end of the bearing box formed in the end frame
Data Source
AI summary
A starter motor is disclosed which includes: 1) a hollow yoke having an open end; 2) a magnetic field system provided on an inner periphery of the yoke; 3) an armature surrounded by the magnetic field system with a predetermined gap therebetween, the armature having an armature shaft; 4) an end frame that closes the open end of the yoke and has a bearing box formed therein, the bearing box being recessed inward of the yoke from an end face of the end frame and having an open end on the end face of the end frame, the bearing box also having a bearing disposed therein to rotatably support an end portion of the armature shaft; and 5) a flexible seal plate that is attached on the end face of the end frame to hermetically seal the open end of the bearing box formed in the end frame.