Electromagnetic Clutch Shift Sleeve With Uniform Switching Force
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Solution Overview
Problem
Existing electromagnetic clutches face challenges in applying a constant and reproducible switching force evenly over the circumference due to uneven radial air gaps and tolerances, which affect the magnetic flux and torque transfer.
Innovation Solution
The electromagnetic clutch design includes a shift sleeve with a separate armature ring guided axially within the stator, ensuring a minimal radial gap and precise alignment, along with an elastic spring unit for controlled movement, to maintain a consistent magnetic force and reduce wear through sliding layers on contact surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the shift sleeve is guided on the shaft with tooth clearance, then the structure is simple, but the radial air gap becomes uneven and switching force cannot be precisely adjusted
Solution Approach 1:
The guidance function is segmented from the shaft to a separate axial guide structure. The shift sleeve is no longer guided directly on the shaft but through this dedicated guide, which isolates the guidance mechanism from the rotational shaft and allows independent optimization of the radial air gap uniformity.
Solution Approach 2:
An axial guide structure is introduced as an intermediary between the shaft and the shift sleeve. This guide mediates the guidance function while maintaining a uniform radial air gap between the stator and shift sleeve, preventing the uneven gap that would otherwise result from direct shaft guidance with tooth clearance.
2Force
If the radial air gap is reduced to minimize magnetic flux path, then switching force increases, but frictional forces from uneven gaps create radial forces that hinder movement
Solution Approach 1:
The radial air gap is optimized locally through the axial guide structure to be uniform and minimal across the entire circumference. This ensures that the magnetic flux path is minimized (maximizing switching force) while the uniformity prevents localized radial forces that would create friction and hinder movement.
Solution Approach 2:
The axial guide structure creates a uniform radial air gap that equates the magnetic potential distribution around the circumference. This eliminates potential differences that would otherwise create radial forces and friction, allowing smooth shift sleeve movement while maintaining strong switching force.
3Manufacturing precision
If tolerances are tight to ensure uniform radial gap, then switching force is consistent, but manufacturing cost and complexity increase
Solution Approach 1:
The axial guide structure serves as an intermediary that actively maintains uniform radial gap between the stator and shift sleeve. This guide compensates for manufacturing tolerances in the shaft and clutch body, allowing larger tolerances elsewhere while still achieving consistent radial gap and reliable switching force.
Solution Approach 2:
The design changes the critical parameter for gap uniformity from the shaft-clutch body interface to the axial guide-stator interface. By controlling the gap at this new interface through the guide structure, the system achieves consistent radial gap with more relaxed tolerances on other components.
4Device complexity
If the armature ring is integrated with the shift sleeve, then the structure is simpler, but wear occurs during rotation due to relative movement
Solution Approach 1:
The armature ring is segmented from the shift sleeve into a separate component. This allows the armature ring to be fixed to the stator without rotation, eliminating wear, while the shift sleeve remains a separate component that engages and disengages without carrying the armature function.
Solution Approach 2:
The magnetic field acts as an intermediary to transmit force from the stationary armature ring to the moving shift sleeve. This eliminates the need for direct mechanical connection between rotating and stationary parts, preventing wear while maintaining force transmission.
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 design achieves a constant and reproducible switching force that acts evenly over the circumference, reducing wear and power loss while ensuring reliable engagement and disengagement of the clutch.
Implementation Method 1
a coil (30) which serves to adjust an armature ring (38) linearly along the first shaft (12)
Implementation Method 2
the magnetic flux through the components also creates radial forces, which hinder the movement of the shift sleeve due to frictional forces
Data Source
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AI summary
The invention relates to an electromagnetic clutch with a shift sleeve (16) which is rotationally fixed on a first shaft (12) and is linearly adjustable along the first shaft (12) between an engaged and disengaged state, a clutch body (20) which is aligned coaxially with the first shaft (12), a stator (26) which includes a coil (30) which serves to linearly adjust an armature ring (38) along the first shaft (12), wherein the armature ring (38) is radially mounted separately from the first shaft (12) and the clutch body (20) in an axial guide (52), wherein an adjustment of the armature ring (38) by means of the coil (30) also results in an adjustment of the shift sleeve (16). The invention also relates to a method for engaging and disengaging an electromagnetic clutch (10).