Sealed Fan Motor Connector Housing to Prevent PCB Deformation
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Solution Overview
Problem
The deformation of circuit boards during the injection of synthetic resin for sealing can lead to defects such as cracks and peeling at solder bonding parts in fan motors, especially when a connector housing is formed integrally with the housing and a gate opening is located near the connector.
Innovation Solution
A fan motor design featuring a tubular bearing holder formed by insert molding with a base part integral to the housing, where the stator is mounted on the bearing holder, and the circuit board is electrically connected to the stator coil, extending from the base part to the connector housing. The synthetic resin seals the components except for the end faces of the bearing holder, with ribs on the connector housing contacting the circuit board to prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a gate opening is provided in the vicinity of the connector for easy access, then the sealing process becomes easier and more accessible, but the circuit board may be deformed by the injection pressure of the injected synthetic resin
Solution Approach 1:
Ribs are preliminarily formed on the connector housing at positions that will contact the circuit board during resin injection. These ribs create preliminary counteracting forces against the injection pressure before the actual deformation occurs, preventing the circuit board from bending or deforming during the sealing process while maintaining gate opening accessibility.
2Device complexity
If the connector housing is formed integrally with the housing, then the structure becomes more compact and simplified, but the circuit board is more susceptible to deformation from resin injection pressure
Solution Approach 1:
The integral connector housing includes preliminarily formed ribs that extend toward the circuit board. These ribs are positioned to make contact with the circuit board during resin injection, creating counteracting forces that prevent deformation. This allows the benefits of integral housing formation while mitigating the deformation risk through the rib structure.
3Reliability
If synthetic resin is injected to seal the stator and circuit board, then the sealing and protection is improved, but defects such as cracks at solder bonding parts or peeling may occur due to injection pressure
Solution Approach 1:
Ribs are preliminarily formed on the connector housing to contact and support the circuit board during resin injection. These ribs create preliminary counteracting forces that distribute and reduce the injection pressure on the circuit board, preventing excessive stress concentration at solder bonding parts and avoiding cracks or peeling defects while maintaining effective sealing.
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 design effectively prevents circuit board deformation during resin injection, ensuring reliable electrical connections and reducing the risk of defects like cracks and peeling at solder bonding parts.
Implementation Method 1
a gate opening that is injected with the synthetic resin at the time of sealing
Implementation Method 2
rids that are at an opposite side to the gate opening with the circuit board between the ribs, and tops of the ribs making contact with the circuit board
Implementation Method 3
The bearing holder is tubular and is formed by insert molding with a base part that is integral with a housing and a connector housing
Data Source
AI summary
A fan motor according to an embodiment includes a bearing holder, a stator, a circuit board, and a synthetic resin. The stator is mounted at an outer circumference of the bearing holder. The circuit board is electrically connected to a coil of the stator, is mounted at a surface of the base part at an opposite side to the bearing holder, and extends from a base part to a connector housing. The synthetic resin seals the bearing holder, the stator, and the circuit board, except for both end faces of the bearing holder. The connector housing has a gate opening that is injected with the synthetic resin at the time of sealing and ribs that are at an opposite side to the gate opening with the circuit board between the ribs, and tops of the ribs making contact with the circuit board.