Magnetic Clutch Engagement for Smooth Bidirectional Torque Transfer
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Solution Overview
Problem
Existing bidirectional couplers and magnetic clutches in additive manufacturing systems experience abrupt locking and relative rotation issues, leading to shock and inefficiency when engaging and disengaging, particularly when the inner shaft rotates and the ball bearing moves outward.
Innovation Solution
A bidirectional magnetic clutch with a concentric arrangement of inner and outer drive members, featuring radially moveable roller members and a magnetic biasing system, allows for smooth engagement and disengagement by using a magnet actuator to align recesses and apply an external magnetic field, enabling torque transfer in both rotational directions without sudden shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bidirectional coupler uses a ball bearing held by a magnet in the inner shaft, then the inner shaft can be locked to the outer shaft at high rotational speeds, but the locking occurs abruptly with shock when the ball bearing suddenly engages the end portions of the slots
Solution Approach 1:
The patent introduces an intermediate mechanism - a cam-shaped groove in the inner shaft that guides the ball bearing during engagement. This cam groove acts as a mediator that converts the abrupt radial movement of the ball bearing into a gradual engagement process, allowing the ball to roll smoothly into position rather than suddenly impacting the slot end, thereby reducing shock while maintaining locking reliability
Solution Approach 2:
The patent makes the engagement process dynamic by utilizing the rotational motion of the inner shaft itself to drive the ball bearing along the cam groove path. As the inner shaft rotates, the cam groove automatically guides the ball through a controlled engagement sequence, transforming a static abrupt lock into a dynamic smooth engagement that occurs progressively during rotation
2Reliability
If the inner shaft must have a non-zero rotational speed to dislocate the ball bearing toward the outer ring, then the locking function can be achieved, but the clutch cannot engage or disengage when stationary or at low speeds
Solution Approach 1:
The patent replaces the purely mechanical centrifugal force mechanism (which requires rotational speed) with a magnetic field-based control system. The magnet in the inner shaft can actively dislocate the ball bearing toward the outer ring through magnetic force alone, enabling engagement and disengagement at any speed including zero, while still maintaining reliable locking when rotated
3Adaptability or versatility
If multiple bidirectional magnetic clutches are used for selecting filament feeders, then convenient magnetic clutch selection arrangement is achieved, but the device complexity increases
Solution Approach 1:
The patent designs each bidirectional magnetic clutch with universal characteristics - the same structural design, magnetic field control mechanism, and engagement principles are applied to all clutches in the system. This universality allows multiple clutches to be used for feeder selection while minimizing overall complexity, as each unit is identical and can be independently controlled through the same actuation methodology
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 reliable, efficient, and smooth coupling and decoupling of drive and driven members, allowing for reliable filament management in additive manufacturing systems by preventing abrupt locking and enabling easy selection and rotation of filament materials, resulting in a compact and efficient design.
Implementation Method 1
The inner drive member is further provided with a magnetic biasing system configured to magnetically bias the roller members into the outward facing recesses through a biasing magnetic field
Implementation Method 2
the magnet actuator is configured to provide an external magnetic field for maintaining an engaged state of the bidirectional magnetic clutch in which the at least two outward facing recesses and the at least two inward facing recesses are substantially aligned and the roller members are magnetically attracted into the inward facing recesses by the external magnetic field
Data Source
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AI summary
A bidirectional magnetic clutch for an additive manufacturing system, comprising a concentric arrangement of an inner drive member (2) and an outer drive member (3) enclosing the inner drive member (2), the inner and outer drive members (2,3) being rotatable relative to each other. The inner drive member (2) comprises at least two outward facing recesses (5, 6) and the outer drive member (3) comprises at least two inward facing recesses (8,9). Each outward facing recess (5,6) comprises a radially moveable roller member (10,11) of ferromagnetic material. The inner drive member (2) further comprises a magnetic biasing system (12) configured to magnetically bias the roller members (10,11) into the outward facing recesses (5,6). The bidirectional magnetic clutch further comprises a magnet actuator (13) at least partially circumferentially arranged around the outer drive member (3) and configured to maintain an engaged state or disengaged state of the bidirectional magnetic clutch.