Electromagnetic Coupling Rotor Structure for Vibration-Resistant Flux Transfer
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Solution Overview
Problem
Existing rotors for transmitting movement to vehicle cooling fans are prone to damage from engine vibrations, leading to fractures and disruption of the magnetic circuit, and struggle to efficiently transmit electromagnetic flux from the outer to the inner zone, especially in high-vibration conditions, while also requiring compact dimensions and high torque performance.
Innovation Solution
A composite rotor design featuring annular gaps filled with non-magnetic material and strategically placed ferromagnetic elements, such as pins and annular plates, to enhance magnetic flux passage and mechanical resistance, allowing for efficient torque transmission and operation at varying fan speeds without increasing component count or size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the rotor is made with continuous circumferential gaps filled with non-magnetic material, then the mechanical strength and resistance to vibration-induced fractures is improved, but the magnetic flux passage from outer to inner zone is blocked
Solution Approach 1:
The rotor is divided into multiple magnetically isolated annular sectors by circumferential gaps filled with non-magnetic material. This segmentation prevents magnetic flux from short-circuiting through the rotor body while maintaining mechanical integrity against vibrations.
Solution Approach 2:
Different regions of the rotor are given different magnetic properties: the gaps are non-magnetic to block flux radially, while ferromagnetic elements (pins, plates) are strategically placed to guide and concentrate flux where needed, creating localized magnetic pathways.
2Reliability
If the rotor design includes multiple ferromagnetic elements and gaps, then the resistance to vibration damage is improved, but the device complexity increases
Solution Approach 1:
Multiple ferromagnetic elements (pins, annular plates) and the gap structures are integrated into a unified rotor design where each element serves dual purposes: mechanical reinforcement against vibration and magnetic flux guidance. This merging reduces the need for separate components.
Solution Approach 2:
The circumferential gaps serve multiple functions: they provide mechanical reinforcement to prevent fractures, act as magnetic isolators to control flux paths, and structurally divide the rotor into functional sectors. This multi-functionality reduces overall device complexity.
3Volume of moving object
If the rotor maintains compact dimensions, then the device size is reduced, but the torque transmission performance may be compromised
Solution Approach 1:
The rotor uses strategic placement of ferromagnetic elements to concentrate and optimize magnetic flux density in key torque transmission zones. By changing the distribution and positioning parameters of these elements, high torque is achieved within compact dimensions without requiring larger rotor volume.
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 rotor design provides enhanced resistance to engine vibrations, maintains high torque transmission efficiency, and enables operation at different fan speeds with reduced risk of damage, while minimizing component count and size, thus reducing production and maintenance costs.
Implementation Method 1
circumferential hollow slot 35 formed along a diameter slightly greater than the diameter of the sleeve 31b and filled with a non-magnetic material 35a, as well as radially outer eyelets 36,37 suitable for creating a magnetic flux deviated along a respective first inner armature 33 and a second outer armature 34
Implementation Method 2
devices which comprise an electromagnetic clutch arranged between an actuating rotor and the fan, which clutch transmits the movement to the fan via two armatures which are respectively and selectively recallable against the rotor by means of excitation of the electromagnet
Implementation Method 3
radially outer eyelets 36,37 suitable for creating a magnetic flux deviated along a respective first inner armature 33 and a second outer armature 34
Data Source
Figure 1a~3
Figure 4~7
Figure 8a~9c
AI summary
Rotor for electromagnetic couplings, comprising: - an annular body (131) made of ferromagnetic material for transporting a magnetic flux, with: --) a coaxial sleeve (131b) extending inwards in an axial direction (X-X) and suitable for coupling with a support shaft (120); --) a continuous, circumferential, non-magnetic, inner recess (135) formed in the front surface of the annular body (131) along a diameter slightly greater than the diameter of the sleeve (132); --) at least one non-magnetic outer recess (636) arranged at least partially along a circumference concentric with said inner recess (135) and with a diameter comprised between the outer diameter of the front surface and the diameter of said inner recess (135); --) at least one non-magnetic intermediate recess (637) arranged at least partially along a circumference concentric with said inner recess (135) and with a diameter comprised between the diameter of the non-magnetic outer recess and the diameter of said inner recess (135); --) means for passage of the magnetic flux, in a radial direction of the recesses filled with non- magnetic material (636a, 637a), between a rotor sector radially comprised between the outer diameter of the annular body and the diameter of said radially outer non-magnetic recess and a rotor sector radially comprised between the diameter of the inner recess (135) and the diameter of the intermediate recess (637).