Three-Speed Fan Drive Using Dual Electromagnetic and Eddy Couplings
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Solution Overview
Problem
Existing devices for driving fans in motor vehicles to cool coolant face issues with excessive wear due to small air-gaps and high torque loads, energy consumption, and the need for compact, cost-effective designs that ensure safe operation even in power supply failures.
Innovation Solution
A device with a fixed axial sleeve, dual electromagnetic couplings, and a Foucault coupling allows for three-speed operation of the fan, with reduced wear, lower power consumption, and a 'Fail Safe' mode using permanent magnets for continued cooling in case of power loss, featuring a compact design with fewer high-cost parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a small air-gap is used between the rotor of the second clutch and the fixed electromagnet, then the compactness of the device is improved, but excessive wear occurs due to accidental contact from vibrations and tolerances
Solution Approach 1:
The patent introduces a flexible membrane as an intermediary element between the rotor and the electromagnet. This membrane allows for controlled deformation that accommodates vibrations and tolerances while maintaining the necessary magnetic coupling, thus preventing excessive wear without requiring a larger air-gap
Solution Approach 2:
The flexible membrane is designed to beforehand cushion the impacts and vibrations that occur during operation. By absorbing these shocks in advance through its elastic properties, it prevents direct contact and wear between the rotor and electromagnet surfaces
2Adaptability or versatility
If multiple components are mounted on the axial extension of the rotor, then the functional requirements for three-speed operation are met, but high torques and large projecting loads act on the rotor
Solution Approach 1:
The patent divides the torque transmission function into multiple independent electromagnetic couplings (first clutch, second clutch, and Foucault coupling). Each coupling handles a specific speed range or function, distributing the torque loads across separate components rather than concentrating them all on a single rotor
Solution Approach 2:
The patent replaces mechanical torque transmission through a single overloaded rotor with electromagnetic torque transmission through multiple independent couplings. This substitution allows for better load distribution and eliminates the need for a large projecting rotor to handle all torque requirements
3Speed
If the brake is engaged to stop fan rotation, then the fan can be completely stopped, but power is consumed due to the resistive torque of the Foucault coupling
Solution Approach 1:
The patent extracts the Foucault coupling from the continuous torque transmission path and uses it only for specific speed reduction functions. By separating its function from continuous power transmission, the system avoids unnecessary energy consumption while still achieving complete fan stopping when needed
Solution Approach 2:
The Foucault coupling is engaged periodically or selectively rather than continuously. It is activated only when specific speed transitions are required, rather than being constantly loaded, thus reducing overall power consumption while maintaining the ability to stop the fan completely when necessary
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 solution enables efficient, low-cost, and safe fan operation with reduced wear and energy consumption, ensuring reliable cooling across varying conditions while maintaining compact dimensions and ease of installation.
Implementation Method 1
a first electromagnetic coupling (100) comprising a first electromagnet (110); a second electromagnetic coupling (200), comprising a second electromagnet (210) mounted on the axial sleeve (10)
Implementation Method 2
an eddy current or Foucault coupling (300) arranged between the movement generation means and the fan support (1a)
Data Source
Figure 1~2
AI summary
Device for driving at three speeds a fan (1 ) for cooling the coolant in a motor vehicle, comprising: a fixed axial sleeve (10) designed to be fastened to a base (1 1 ) of the vehicle engine; a fan support (1 a) for carrying the fan (1 ); a first electromagnetic coupling (100) comprising a first fixed electromagnet (1 10), a first rotor (120); a second electromagnetic coupling (200) comprising a fixed electromagnet (210) mounted on the axial sleeve (10), a second rotor (220) and an armature (240) axially arranged on the opposite side to the second electromagnet (210) relative to the second rotor (220) and rotationally integral with the rotor (120) of the first coupling; an eddy current or Foucault coupling (300). The first coupling, the second coupling and the Foucault coupling are arranged between means (121 ) for taking up a rotational movement and the support (1 a) of said fan (1 ), and the first rotor and the second rotor (220) are mounted on a respective bearing (121,221 ) keyed on the fixed axial sleeve (10), wherein a driving part of the Foucault coupling (300) is mounted on the second rotor (220) and the driven part of the Foucault coupling is integral with the support (1 a) of the fan (1 ), so that the excitation of only the electromagnet (210) of the second coupling (200) causes rotational driving of the fan support (1 a) at a speed slower than that of the first rotor (120), by means of the Foucault coupling (300).