Motor Shaft Sensing Magnet Coupling for Secure Compact Assembly
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Solution Overview
Problem
The existing methods for coupling a sensing magnet to a shaft in motors face challenges such as inaccurate adhesion, potential separation, increased magnetic flux leakage, chip generation, short-circuits, deformation, and slipping, especially in limited assembly spaces.
Innovation Solution
A motor design utilizing a coupling member with an elastic force, featuring a cylindrical body and a donut-shaped sensing magnet, where the coupling member is press-fitted into a groove on the shaft, providing secure assembly and positioning without adhesives or press fitting, and includes an adhesive member for additional fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the sensing magnet is fixed to the shaft using adhesive, then the assembly process is simple, but the adhesion process is difficult to manage accurately and the sensing magnet may separate from the shaft
Solution Approach 1:
A coupling member is introduced as an intermediary component between the sensing magnet and the shaft. The coupling member includes a coupling portion that fits into a groove on the shaft and an accommodation portion that holds the sensing magnet, thereby mediating the connection and eliminating the need for adhesive while ensuring reliable fixation
Solution Approach 2:
The connection system is segmented into three distinct components: the shaft with a groove, the coupling member with coupling and accommodation portions, and the sensing magnet. This segmentation allows each component to be optimized independently and assembled without adhesive, solving both the simplicity and reliability issues
2Ease of manufacture
If the sensing magnet is attached to the end portion of the shaft, then the assembly is straightforward, but the magnetic flux leaking from the sensing magnet to the shaft is increased
Solution Approach 1:
The coupling member acts as a non-magnetic intermediary barrier between the sensing magnet and the magnetic shaft. This intermediary prevents direct magnetic flux leakage from the sensing magnet to the shaft while maintaining the straightforward end-portion assembly configuration
Solution Approach 2:
The coupling member is strategically positioned only at the interface between the sensing magnet and shaft, providing localized non-magnetic shielding exactly where needed to prevent flux leakage, without affecting other areas of the assembly
3Reliability
If the sensing magnet is coupled to the shaft using press fitting method, then the fixation is secure, but chips may be generated causing short-circuit problems
Solution Approach 1:
The coupling member serves as a mediator that eliminates direct press-fitting contact between the sensing magnet and shaft. The coupling portion fits into the groove without excessive force, preventing chip generation while the coupling structure itself provides secure fixation
Solution Approach 2:
The mechanical press-fitting system is replaced with a groove-based coupling system. Instead of forcing the magnet onto the shaft (which generates chips), the coupling member engages with the groove through a controlled mechanical interface that secures the magnet without damaging either component
4Strength
If the sensing magnet is excessively press-fitted to the shaft, then the fixation is strong, but the sensing magnet or shaft may be deformed
Solution Approach 1:
The coupling member distributes the fixation forces across multiple contact points (coupling portion in groove, accommodation portion holding magnet) rather than concentrating force at a single interface. This intermediary structure provides strong fixation while preventing deformation of both the sensing magnet and shaft
5Stability of the object's composition
If the sensing magnet is too loosely press-fitted to the shaft, then the components are not damaged, but slipping occurs between the sensing magnet and shaft
Solution Approach 1:
The coupling member acts as a positive mechanical coupling that prevents slipping between the sensing magnet and shaft. The coupling portion engaged in the groove and the accommodation portion holding the magnet create a rigid connection that ensures rotational synchronization without excessive press-fit force
Solution Approach 2:
The coupling member features curved or tapered surfaces (second region obliquely bent upward, third region bent outward) that guide the sensing magnet into proper position and maintain tight engagement without requiring excessive force, preventing slipping while protecting components from damage
6Volume of moving object
If the sensing magnet is positioned at the upper end of the shaft in limited space, then the assembly is compact, but the assembly space for assembling the sensing magnet to the shaft is very small
Solution Approach 1:
The assembly is segmented into modular components (shaft with groove, coupling member with coupling and accommodation portions, sensing magnet) that can be assembled in a standardized sequence. This segmentation allows the coupling member to be inserted into the groove first, providing a guide and working space for subsequent magnet installation, even in compact configurations
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 ensures secure and reliable assembly of the sensing magnet on the shaft, prevents contamination and damage, maintains precise positioning, and facilitates easy installation even in confined spaces, enhancing the motor's performance and reliability.
Implementation Method 1
the coupling member includes a coupling portion, which has an elastic force and of which at least a part is inserted into and coupled to the first groove
Data Source
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AI summary
An embodiment relates to a motor including a shaft, a rotor coupled to the shaft, a stator disposed outside the rotor, a sensing magnet disposed on the shaft, and a coupling member disposed to cover the sensing magnet, wherein the coupling member is inserted into a first groove concavely formed in an end portion of the shaft. Accordingly, combinability and assemblability of the sensing magnet and the shaft can be secured using the coupling member formed to have an elastic structure in the motor.