Front-Coil Viscous Clutch Layout for Compact Fan Torque Control
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Solution Overview
Problem
Existing viscous clutches for cooling fans in internal combustion engines consume significant power when cooling is not needed, leading to inefficiencies in fuel consumption and noise, and there is a need for a compact and easily installable assembly with improved torque control.
Innovation Solution
A viscous clutch assembly with a rotationally fixed center shaft, a rotor, housing, and a modular valve subassembly controlled by a front-mounted electromagnetic coil, featuring a compact magnetic flux circuit and a flux guide to minimize air gaps, allowing for efficient torque transmission and selective fan operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a viscous clutch assembly with front-mounted electromagnetic coil and compact flux circuit is used, then power consumption is reduced and torque control is improved, but device complexity increases due to modular valve subassembly and flux guide components
Solution Approach 1:
The viscous clutch assembly is divided into modular subassemblies including a valve subassembly with separate armature, pole, and reed valve element components. This segmentation allows for optimized magnetic flux paths in each module while reducing overall power consumption through targeted electromagnetic actuation of individual components.
Solution Approach 2:
A flux guide is introduced as an intermediary component between the electromagnetic coil and the valve subassembly. This flux guide directs and concentrates magnetic flux lines, improving the efficiency of electromagnetic actuation and reducing the power required to operate the valve while maintaining precise torque control.
2Ease of manufacture
If modular valve subassembly with reed valve element is implemented, then ease of assembly is improved, but manufacturing precision requirements increase due to tight tolerances for valve clearance and magnetic flux path alignment
Solution Approach 1:
The valve subassembly is segmented into separate components (armature, pole, reed valve element) that can be pre-assembled and tested independently before final installation. This allows for precise adjustment of valve clearances and magnetic flux path alignment during subassembly fabrication, while the modular design simplifies final installation and replacement procedures.
Solution Approach 2:
The modular valve subassembly is pre-assembled with pre-adjusted clearances and pre-aligned magnetic flux paths before installation in the viscous clutch. This preliminary preparation ensures that critical tolerances are met during manufacturing while simplifying the final assembly process, as the subassembly requires minimal adjustment upon installation.
3Power
If flux guide and magnetic flux insulating material are added, then torque control is improved through minimized air gaps, but weight of stationary object increases
Solution Approach 1:
Magnetic flux insulating material is applied locally at specific positions where flux leakage would occur, such as at the interfaces between magnetic components and at the edges of the flux guide. This targeted application minimizes air gaps and improves torque control only where necessary, rather than adding insulation throughout the entire assembly, thus reducing unnecessary weight.
Solution Approach 2:
The flux guide is constructed using composite materials that combine high magnetic permeability with structural strength. This allows the flux guide to effectively direct magnetic flux and minimize air gaps for improved torque control, while the optimized material composition and geometry reduce the overall weight compared to traditional solid metal construction.
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 provides a compact and efficient viscous clutch mechanism that reduces power consumption, improves torque control, and facilitates easy assembly, enhancing fuel efficiency and reducing noise by allowing continuous adjustment of fan operation.
Implementation Method 1
an electromagnetic coil located at or near the front end of the center shaft and being rotationally fixed, a valve subassembly operable to control flow of a shear fluid between the reservoir and the working chamber and controllable using magnetic flux generated by the electromagnetic coil
Implementation Method 2
A flux circuit connects the electromagnetic coil and the valve subassembly, such that the flux circuit is located forward of the rotor and passes through the flux guide and a portion of the center shaft
Implementation Method 3
a magnetic flux insulating material positioned adjacent to and radially inward from the flux guide
Data Source
AI summary
A viscous clutch assembly includes a rotationally fixed center shaft, a rotor rotatably supported on the center shaft, a housing rotatably supported on the center shaft, a working chamber, a reservoir carried by the rotor, an electromagnetic coil located at or near a front end of the center shaft, a valve subassembly magnetically operable to control flow of a shear fluid between the reservoir and the working chamber, a flux guide extending axially across a cover of the housing, and a magnetic flux insulating material positioned adjacent to and radially inward from the flux guide. A flux circuit located forward of the rotor connects the electromagnetic coil and the valve subassembly and passes through the flux guide and the center shaft, with the magnetic flux insulating material at least partially surrounded by the flux circuit.