Segmented Heat Pump Grille for Finger-Safe Large Outdoor Units
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Solution Overview
Problem
The challenge is to design a larger grille for outdoor units of air heat pumps that meets finger safety standards while being cost-effective to manufacture, as current grilles often exceed the capacity of standard injection molding machines and may have weak spots due to large tolerances.
Innovation Solution
The grille is divided into two separate parts with a hub portion, allowing for standard injection molding and enhanced strength through engagement members and fixation members, which are connected to form a single, rigid unit that meets finger safety tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the grille is made as a single large piece to cover the entire front of the outdoor unit, then the finger safety coverage is improved, but the manufacturing cost increases and standard injection molding machines cannot be used
Solution Approach 1:
The grille is divided into multiple separate parts (first grille part, second grille part, third grille part) that can be manufactured using standard injection molding machines. These segmented parts are then assembled together to form the complete grille structure, maintaining both manufacturability and safety coverage.
Solution Approach 2:
Multiple separately manufactured grille parts are combined through engagement members (such as clips, tabs, or interlocking features) to form a unified grille assembly that provides complete front coverage for finger safety while being produced from smaller, manufacturable components.
2Reliability
If the grille size is increased to cover the entire front of larger outdoor units, then the safety coverage is improved, but the grille develops weak spots due to large tolerances in molding
Solution Approach 1:
By dividing the large grille into smaller separate parts, each part can be molded with tighter tolerances and fewer weak spots. The segmentation allows each component to be optimized for strength while maintaining the overall safety coverage.
Solution Approach 2:
The separate grille parts are joined using engagement members that create strong mechanical connections between parts. This merging process distributes structural loads across multiple connection points, preventing weak spots that would occur in a single large molded piece.
3Shape
If the grille is made as a single large piece, then the aesthetic appearance is improved, but the manufacturing requires specialized expensive machines
Solution Approach 1:
The grille is segmented into multiple parts that can be manufactured on standard, cost-effective injection molding machines. The segmentation enables production using widely available equipment rather than requiring specialized large-capacity molding machines.
Solution Approach 2:
The separate manufactured parts are assembled into a unified grille structure that maintains aesthetic appearance. The engagement members and joining mechanisms are designed to be visually acceptable while enabling production on standard equipment.
4Reliability
If the grille covers the entire front of the outdoor unit, then the finger safety compliance is improved, but the manufacturing tolerances increase leading to weak spots
Solution Approach 1:
Dividing the grille into smaller separate parts allows each part to be molded with tighter, more controlled tolerances. The smaller mold cavities provide better dimensional control and reduce the accumulation of tolerance errors that occur in large single-piece molding.
Solution Approach 2:
The precisely manufactured separate parts are assembled using engagement members that maintain tight tolerances at the joints. This merging process ensures that the overall assembly meets finger safety compliance requirements while maintaining manufacturing precision through controlled connections.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
Outdoor unit (10) for a heat pump comprising a refrigerant circuit, the outdoor unit (10) comprising a casing (11) comprising a front, a fan (50) accommodated in the casing, the fan (50) having fan blades (55) rotatable about an axis of rotation (56), a grille (100) arranged at the front and covering the fan blades (55), the grille (100) comprising a plurality of openings (102) along air to pass the grille, wherein the grille comprises at least two separate parts (113, 114) each of the parts comprising at least one of the openings (102) .