Brushless Rotor Adhesive Bonding for Thermal Expansion
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Solution Overview
Problem
Existing methods for producing magnetic rotors are complex, require precise shapes, suffer from thermal expansion issues, and involve multiple stages, leading to increased costs and production time.
Innovation Solution
A rotor design for brushless electric machines featuring a cylinder head, motor magnet, and piston, where the motor magnet is glued to the cylinder head and piston using an adhesive joint distributed across varying diameters, allowing for high viscosity glue application and accommodating high tolerances, ensuring concentricity and rotational locking without complex internal shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex shapes are used for the rotor and magnet to ensure retention and torque transmission, then bonding reliability is improved, but device complexity increases and manufacturing difficulty increases
Solution Approach 1:
The invention divides the bonding function into two separate components: the cylinder head provides the bonding surface and adhesive distribution, while the piston provides the retention function. This segmentation allows each component to have a simple geometry while collectively achieving both bonding reliability and retention without requiring complex shapes in either component.
Solution Approach 2:
The adhesive acts as an intermediary substance between the cylinder head and the magnet ring, enabling reliable bonding without requiring complex interlocking shapes. The adhesive fills the bonding interface and creates a strong chemical and mechanical bond, replacing the need for complex geometric features.
2Manufacturing precision
If multiple production stages are used to ensure precise assembly and bonding, then manufacturing precision is improved, but productivity decreases and production time increases
Solution Approach 1:
The piston is pre-assembled on the rotation axis with the cylinder head before the magnet ring is installed. This preliminary assembly establishes precise concentricity and positioning, allowing the magnet ring to be bonded in a single operation without requiring multiple adjustment and bonding stages, thereby improving both precision and productivity.
Solution Approach 2:
The invention combines the positioning, retention, and bonding functions into a single assembly operation. The piston and cylinder head together provide both positioning and retention features, allowing the magnet ring to be bonded in one continuous process rather than through multiple separate stages.
3Device complexity
If adhesive is applied in a limited space without proper distribution mechanism, then device complexity is reduced, but adhesive distribution becomes non-uniform and bonding quality decreases
Solution Approach 1:
The adhesive is pre-applied to the piston or cylinder head surface before assembly, allowing it to spread uniformly across the bonding interface. This preliminary application ensures even distribution without requiring complex distribution mechanisms during the bonding process.
Solution Approach 2:
The invention utilizes the viscosity and flow properties of the adhesive as a parameter, selecting adhesives with appropriate viscosity that allow spontaneous uniform spreading in the bonding space. By controlling the adhesive's physical parameters, uniform distribution is achieved without adding structural complexity for distribution mechanisms.
4Manufacturing precision
If low viscosity adhesive is used to ensure proper spreading, then adhesive distribution is improved, but adhesive strength and bonding reliability decrease
Solution Approach 1:
The invention optimizes the viscosity parameter of the adhesive to a specific range that balances spreading capability and bonding strength. By carefully selecting and controlling the adhesive's viscosity parameter, the system achieves both uniform distribution and high bonding reliability without requiring extreme values.
Solution Approach 2:
The adhesive is applied in a controlled manner before final assembly, allowing it to spread to the required extent while maintaining adequate viscosity for strong bonding. This timing control enables the use of higher viscosity adhesives that provide better strength while still achieving uniform distribution during the assembly process.
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 solution simplifies the production of magnetic rotors, allows for the use of parts with different thermal expansion coefficients, ensures even adhesive distribution, and minimizes the number of parts required, enabling the assembly of large and long magnets with high accuracy and reliability.
Implementation Method 1
the motor magnet being glued to the cylinder head and to the piston by an adhesive joint distributed between the diameters DA and DC2 and between DA and DP
Data Source
Figure 1a~2
Figure 3~5
Figure 6~7
AI summary
The present invention relates to a magnetized moving part, and notably to a rotor (1) for a brushless electric machine comprising a field frame (3), a motor magnet (4) and a piston (5), characterized in that the motor magnet (4) has an inside diameter DA, the field frame (3) has an outside diameter DC2, and the piston (5) has an outside diameter DP, these diameters being such that DA is greater than the diameters DC2 and DP, and in that the motor magnet (4) is bonded to the field frame (3) and to the piston (5) by an adhesive joint spread between the sections DA and DC2 and between DA and DP. The invention also relates to a method of manufacturing such a part.