Torque Rotor Partition Rib Design for Injection Molding
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Solution Overview
Problem
Conventional torque rotor manufacturing processes lead to plastic inflow between the yoke and magnet during injection molding, causing magnet roundness degradation, potential magnet damage due to temperature expansion differences, and idle rotation issues, resulting in inaccurate torque measurements and potential magnet breakage.
Innovation Solution
A torque rotor design featuring a magnet with alternately repeated N and S poles, a yoke inserted into the magnet, and a tube inserted into the yoke, with a fixing mechanism using protrusions, grooves, and adhesive coating to prevent plastic inflow and relative movement between components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plastic injection molding is used to form the assembling structure, then the structure can be efficiently manufactured, but plastic inflows between the yoke and magnet causing magnet roundness degradation and potential damage
Solution Approach 1:
The invention divides the assembling structure into separate sections by introducing partition ribs that segment the plastic flow paths. These ribs create distinct zones that prevent plastic from infiltrating the critical interface between the yoke and magnet, thereby maintaining manufacturing precision while preserving the efficiency of injection molding
Solution Approach 2:
The partition ribs act as intermediary structures that intervene in the plastic flow path. These ribs serve as barriers that redirect and control the plastic material, preventing it from reaching the yoke-magnet interface while still allowing the injection molding process to proceed efficiently
2Reliability
If the yoke and magnet are assembled with tight fit, then idle rotation is prevented, but the difference in temperature expansion coefficients causes damage to the magnet
Solution Approach 1:
The invention applies different levels of fixation to different regions of the yoke-magnet assembly. The adhesive is selectively applied at specific locations where fixation is needed to prevent idle rotation, while leaving other regions with clearance to accommodate thermal expansion differences, thus preventing magnet damage
Solution Approach 2:
The invention uses a composite fixation approach combining mechanical features (protrusions and grooves) with adhesive bonding. This composite structure provides sufficient anti-idle rotation capability while the adhesive layer also acts as a compliant element that can absorb thermal stress, preventing magnet damage
3Reliability
If adhesive is coated on the yoke and magnet, then idle rotation is prevented, but the coating process adds manufacturing complexity
Solution Approach 1:
The adhesive coating is applied in advance during the assembly process, before the final curing and testing stages. The protrusions and grooves are pre-formed on the components, and the adhesive is applied to these prepared surfaces, streamlining the manufacturing process while ensuring reliable fixation
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
Prevents plastic inflow and temperature-induced damage, ensuring accurate torque measurements and maintaining magnet integrity by preventing idle rotation and eccentricity during rotation.
Implementation Method 1
adhesive coating to prevent plastic inflow and relative movement between components
Implementation Method 2
fixing mechanism using protrusions, grooves, and adhesive coating to prevent plastic inflow and relative movement between components
Implementation Method 3
a magnet with alternately repeated N and S poles for generating magnetic force
Data Source
AI summary
Disclosed is a torque rotor and method for manufacturing the torque rotor having an effect of preventing inflow of plastic between a yoke and a magnet during a conventional plastic injection molding process for forming an assembling structure after assembling between the yoke and the magnet, thereby preventing degradation of a roundness of the magnet or damage of the magnet due to the difference in the temperature expansion coefficients, and preventing idle rotation of the yoke and the magnet relative to each other.