Laminated Blower Wheel Insert for Stable Shaft Engagement
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Solution Overview
Problem
Existing HVAC blower systems face issues with the blower wheel being either too loose or too tight when loaded onto the shaft, leading to inefficiency or failure due to slipping or cracking, especially under thermal cycles and mechanical shock.
Innovation Solution
A blower assembly featuring a laminated insert and rotor with metal sheet layers, where the insert and rotor have matching profiles and rotational relationships, providing a stable joint across temperature conditions, and a plastic blower wheel is overmolded onto the laminated insert for secure engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the blower wheel is made loose on the shaft for ease of assembly, then assembly is easier, but the blower wheel slips under thermal cycles and mechanical shock
Solution Approach 1:
The blower wheel assembly is segmented into multiple components: a shaft, a blower wheel, and an intermediate insert with laminated metal sheets. This segmentation allows each component to be optimized independently - the insert provides a secure metal-to-metal connection for reliability, while the overall assembly remains manageable for assembly operations.
Solution Approach 2:
An insert comprising laminated metal sheets is introduced as an intermediary component between the shaft and the blower wheel. This insert acts as a mediator that provides a stable engagement interface, preventing direct contact between the shaft and blower wheel while ensuring reliable torque transmission under thermal and mechanical stress.
2Reliability
If the blower wheel is made tight on the shaft for secure engagement, then slipping is prevented, but the blower wheel may crack under thermal cycles and mechanical shock
Solution Approach 1:
The rigid connection is segmented into multiple thin laminated metal sheets rather than a single solid piece. This segmentation distributes mechanical and thermal stresses across multiple interfaces, preventing stress concentration that would cause cracking while maintaining secure engagement.
Solution Approach 2:
The insert is constructed from laminated metal sheets, creating a composite structure that combines the benefits of metal strength with the flexibility of layered construction. This composite approach provides secure engagement while accommodating thermal expansion and contraction without cracking.
3Reliability
If a metal insert with multiple laminated sheets is used between the shaft and blower wheel, then engagement stability is improved, but device complexity increases
Solution Approach 1:
The insert combining multiple laminated metal sheets is integrated as a single pre-assembled unit that fits between the shaft and blower wheel. While the internal structure is complex, the insert itself is manufactured as one component, simplifying the overall assembly process and reducing the number of separate parts that need to be handled during assembly.
Solution Approach 2:
The laminated metal sheets are nested within each other to form a compact insert structure. This nesting allows multiple functional layers to be contained within a single external envelope, providing complex engagement characteristics without increasing the overall dimensional footprint of the assembly.
Data Source
AI summary
A blower assembly for an HVAC system includes a blower wheel, which includes a plurality of blades. A laminated insert is concentric with the blower wheel and radially inward of the plurality of blades. A shaft is coupled to the blower wheel through the laminated insert.