Helical Clutch Assembly for Selective Driven Component Operation
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Solution Overview
Problem
Existing driven components with clutch systems, such as coolant pumps and fans, often operate continuously, making it difficult to selectively inhibit their operation, particularly when the engine is cold, leading to inefficiencies in heating and energy consumption.
Innovation Solution
A compact clutch assembly featuring a driving member, a driven member, a wrap spring, and an actuator with an electromagnet and armature, allowing for selective operation by engaging or disengaging the clutch through the expansion and contraction of the wrap spring, enabling the transmission of rotary power only when needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a robust clutching system is integrated into a driven component, then selective operation of the component is achieved, but the device complexity and packaging difficulty increase
Solution Approach 1:
The clutch assembly is integrated directly into the driven component housing, merging the clutch mechanism with the component structure. The driving member is coupled to the power source and the driven member is coupled to the component, with the wrap spring and actuator housed within the same housing as the component, eliminating the need for separate clutch housing and reducing overall system complexity.
Solution Approach 2:
The actuator with electromagnet and armature is nested within the housing, with the armature positioned to interact with the wrap spring. The wrap spring is positioned between the driving member and driven member, nested within the compact space. This nested arrangement allows multiple components to occupy overlapping spatial volumes, reducing the overall packaging footprint.
2Reliability
If continuous operation of driven components is maintained, then reliable power transmission is ensured, but energy consumption increases and engine heating is delayed
Solution Approach 1:
The clutch system transitions from static continuous engagement to dynamic selective engagement. The wrap spring dynamically adjusts the connection between driving and driven members based on actuator position. When the armature moves to the second position, the wrap spring expands and disengages the clutch, allowing selective inhibition of component operation while maintaining the ability to re-engage when needed.
Solution Approach 2:
The clutch enables periodic engagement and disengagement of the driven component during engine operation. The component can be selectively engaged when power transmission is needed and disengaged when energy conservation or rapid engine heating is desired, replacing continuous operation with periodic action based on operational requirements.
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 allows for efficient selective operation of driven components, reducing energy consumption and enabling faster engine heating by inhibiting the operation of components like coolant pumps and fans when not necessary, thus optimizing engine performance.
Implementation Method 1
The actuator has an electromagnet, which is mounted coaxially about the driving member, and an armature that is axially movable between a first position and a second position
Implementation Method 2
The wrap spring includes a plurality of helical coils, a tang and an engaging portion. At least a portion of the helical coils is engaged to the clutch surface
Data Source
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AI summary
A component, such as an engine accessory for an automotive engine, that has clutch with a helical clutch coil and an axially movable armature. The helical clutch coil is normally engaged so as to transmit rotary power between a driving member and a driven member. The armature can be moved to apply a force to a tang of the helical clutch coil that causes the helical clutch coil to disengage to an extent where full rotary power is not passed through the clutch to drive the component.