Mixed Flow Fan Ribbed Vault Balancing Pockets Turbulence
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Solution Overview
Problem
Mixed-flow fans experience power loss and reduced performance due to strong turbulence caused by large balancing pockets, leading to early reaching of motor performance limits at low rotation speeds.
Innovation Solution
The fan wheel is designed with a tubular ferromagnetic yoke and a cup-shaped yoke that serve as a magnetic return path and mechanical reinforcement, along with balancing pockets in two parallel planes for easy balancing, and a ribbed vault structure to minimize turbulence, using a ferromagnetic yoke and cup-shaped yoke for magnetic interaction and heat dissipation, and a ribbed vault structure to reduce turbulence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If large balancing pockets are provided in the fan wheel, then balancing is easier, but strong turbulence is caused leading to power loss and reduced performance
Solution Approach 1:
The patent divides the single large balancing pocket into multiple smaller balancing pockets distributed across two parallel planes (first and second planes). This segmentation reduces the size of individual pockets, thereby minimizing turbulence while maintaining effective balancing capability through distributed weight adjustment.
Solution Approach 2:
The patent transitions from a single-plane balancing approach to a two-plane balancing system. By distributing balancing pockets across two parallel planes perpendicular to the rotor axis, the invention adds a dimensional aspect to balancing, enabling better control of rotor dynamics without requiring large single pockets that cause turbulence.
2Strength
If the tubular ferromagnetic yoke is embedded in the impeller material, then mechanical reinforcement is provided, but assembly complexity increases
Solution Approach 1:
The patent combines the tubular ferromagnetic yoke with the impeller material by embedding it directly into the impeller. This merging integrates the magnetic return path function with the mechanical structure, providing both mechanical reinforcement and magnetic functionality through a unified component rather than separate assemblies.
Solution Approach 2:
The tubular ferromagnetic yoke serves multiple functions simultaneously: it provides mechanical reinforcement to the impeller structure, creates a magnetic return path for the external-rotor motor, and defines a central cavity for the cup-shaped yoke. This multi-functionality reduces the need for additional separate components.
3Power
If the cup-shaped yoke with permanent magnet arrangement is press-fitted into the tubular yoke, then magnetic interaction is achieved, but assembly force may cause damage
Solution Approach 1:
The patent implements a nested structure where the cup-shaped yoke containing the permanent magnet arrangement is press-fitted into the tubular ferromagnetic yoke. This nesting arrangement achieves the magnetic interaction function while organizing components in a compact, integrated manner that reduces assembly complexity despite the press-fitting requirement.
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 design enhances fan performance by reducing turbulence, maintaining high efficiency, and simplifying balancing, while preventing hot spots and mechanical damage during assembly.
Implementation Method 1
the permanent magnet arrangement magnetically interacts with the internal stator of the motor
Implementation Method 2
the tubular yoke and the cup-shaped yoke together serve as a ferromagnetic return path for the external-rotor motor. The tubular ferromagnetic yoke performs, on the one hand, a magnetic function for the motor and, on the other hand, forms a kind of mechanical reinforcing backbone for the impeller; these functions do not interfere with one another. At the same time, this part also acts as a cooling element for the motor, which dissipates heat outward, and thereby tends to prevent or counteract formation of hot spots in the interior of the impeller.
Data Source
AI summary
A mixed-flow fan features a housing (42); an impeller (43) journaled rotatably with respect to the housing, and equipped with fan blades (54); a generally cylindrical air conduit (50) defined between the fan housing and the impeller, the fan blades extending into the air conduit in order, during operation, to transport air; an external-rotor motor (75) having an internal stator (100) and an external rotor (81) which includes a tubular ferromagnetic yoke (63) partly embedded in material of the impeller. A cup-shaped yoke (72) fits into a central cavity (68) of the tubular yoke (63) and accommodates a permanent magnet arrangement (66) which interacts with the stator. The tubular yoke (63) and the cup-shaped yoke (72) together serve as a magnetic return path for the external-rotor motor. The structure minimizes damage during final assembly, and simplifies insertion of balancing weights.