Eddy-Current Retarding Device Axial Size Reduction
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Solution Overview
Problem
Conventional eddy-current retarding devices with synchronous rotation type require a friction brake for braking, leading to increased size and vulnerability to foreign substances accumulating between the brake member and magnet, which can deteriorate performance.
Innovation Solution
The design includes a magnet holding member connected to the rotating shaft, surrounded by a brake member that rotates independently, with a friction brake pressing against the brake member to stop it, preventing foreign substances from entering the space between the brake member and permanent magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a friction brake is added to stop the magnet holding member or brake member, then braking capability is improved, but the device size in the axial direction increases
Solution Approach 1:
The friction brake is merged with the brake member structure. The brake member includes a friction brake portion that integrates the braking function directly into the brake member, eliminating the need for a separate friction brake assembly and reducing axial size while maintaining braking capability
Solution Approach 2:
The brake member serves multiple functions: it generates eddy current braking force through interaction with permanent magnets, and simultaneously provides friction braking through its friction brake portion. This multi-functionality reduces the need for separate braking components, thereby reducing axial size
2Reliability
If the magnet holding member and brake member are separated with a gap, then eddy current generation is improved, but foreign substances can accumulate between them causing performance deterioration
Solution Approach 1:
A non-magnetic material layer is introduced as an intermediary between the magnet holding member and brake member. This layer maintains the necessary gap for eddy current generation while preventing foreign substances from accumulating in the space between the components, thus resolving the contradiction between braking efficiency and contamination prevention
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 configuration reduces the device's axial size, prevents foreign substance accumulation, and enhances braking efficiency by generating eddy currents on the inner surfaces of the brake member, ensuring smooth rotation and improved performance.
Implementation Method 1
causes eddy current to be generated on the surface of the brake member opposite to the magnet, due to an effect of a magnetic field from the magnet
Implementation Method 2
an effect of a magnetic field from the magnet
Implementation Method 3
a friction brake that comprises a brake caliper which causes a friction member to squeeze an outer periphery portion of an external surface of each of the paired disk portions from both sides in the axial direction of the brake member at a time of braking to bring the brake member to a stop
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
This eddy-current retarding device includes: a magnet holding member that is coaxially provided to a rotating shaft and holds plural permanent magnets in a circumferential direction; a brake member that includes paired disk portions disposed on both sides of the magnet holding member in the axial direction of the rotating shaft, a connecting portion that connects the paired disk portions, and an eddy-current generating portion that causes eddy current due to rotation of the permanent magnets, and this brake member being supported in a relatively rotatable manner with respect to the rotating shaft; and a friction brake that causes a friction member to press against the brake member at the time of braking to bring the brake member to a stop.