Electromagnetic Clutch Undercut Gearing for Higher Torque
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Solution Overview
Problem
Existing electromagnetic couplings face limitations in transmitting high torque due to restricted switching travel of the shift sleeve, necessitating larger coils that increase installation space, weight, and material costs, particularly in vehicle applications.
Innovation Solution
An electromagnetic clutch design featuring a shift sleeve with undercuts in the toothed sections and a dual-coil mechanism, allowing additional displacement during torque transmission to enhance axial overlap without increasing coil size, combined with spring units for relative movement and holding forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the switching path and axial overlap of the gearing is increased to transmit higher torque, then torque transmission capability is improved, but coil size and weight must be increased
Solution Approach 1:
The patent introduces a dynamic element (spring unit) that allows the shift sleeve to move beyond the static magnetic switching travel limit. The spring stores and releases energy to provide additional axial displacement, enabling greater tooth overlap and higher torque transmission without increasing coil size or weight.
Solution Approach 2:
The patent adds a spring-assisted dimensional extension to the magnetic actuation system. By combining magnetic force (primary dimension) with spring mechanical advantage (secondary dimension), the system achieves extended switching travel and enhanced torque capacity without proportionally increasing electromagnetic component size.
2Power
If larger coils are used to increase switching travel and axial overlap, then torque transmission is improved, but installation space and material costs increase
Solution Approach 1:
The spring unit provides dynamic mechanical advantage, allowing the shift sleeve to achieve greater axial displacement than the magnetic field alone would permit. This enables sufficient tooth engagement for high torque transmission while keeping the coil and overall assembly compact.
Solution Approach 2:
The spring unit acts as an intermediary between the magnetic actuation system and the shift sleeve. It translates the limited magnetic switching travel into extended axial movement, mediating between the constraint of small coil size and the requirement for large tooth overlap.
3Power
If the magnetic switching travel is increased to achieve greater axial overlap, then torque transmission is improved, but the complexity of the electromagnetic system increases
Solution Approach 1:
The patent segments the torque transmission enhancement into two independent functional components: the magnetic actuation system (for initial engagement) and the spring-assisted mechanical system (for enhanced overlap). This segmentation allows each component to be optimized independently without increasing overall system complexity.
Solution Approach 2:
The spring unit serves as a simple mechanical intermediary that bridges the magnetic field and the shift sleeve. This intermediary approach is simpler than redesigning the electromagnetic system itself, as it adds a straightforward mechanical element rather than complicating the electromagnetic actuation mechanism.
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
Enables higher torque transmission with reduced coil size and weight, minimizing installation space and material costs, while maintaining efficient engagement and disengagement through magnetic and spring-assisted mechanisms.
Implementation Method 1
a stator comprising a first coil (26) which serves to adjust the shift sleeve (16) linearly along the shaft (12) into the engaged state
Implementation Method 2
the first and/or second toothed section has undercut(s) in the direction of the engaged state which is/are designed such that a torque transmission between the shaft (12) and the first clutch body (20) generates a force on the shift sleeve (16) in the direction of the engaged state
Data Source
Figure 1
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AI summary
The invention relates to an electromagnetic clutch with a shift sleeve (16) having a first toothed section (18) which is rotationally fixed on a first shaft (12) and is linearly adjustable along the first shaft (12) between an engaged and disengaged state, and a first clutch body (20) having a second toothed section (22) which is aligned coaxially with the first shaft (12), wherein the first and/or second toothed section (18, 22) has undercuts (23, 25) in the direction of the engaged state, which are configured such that a torque transmission between the first shaft (12) and the first clutch body (20) generates a force on the shift sleeve (16) in the direction of the engaged state. The invention also relates to a method for closing and opening an electromagnetic clutch (10).