Magnetorheological Haptic Brake Gaps for Wide-Range Torque Control
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Solution Overview
Problem
Existing magnetorheological brakes have a relatively small working range, characterized by a high basic friction in relation to maximum torque, which is insufficient for fine motor applications requiring lower basic torque with higher maximum torque, leading to fatigue and difficulty in making precise adjustments.
Innovation Solution
A haptic operating device with a magnetorheological braking device featuring two functionally different brake gap sections, one generating high torque at lower speeds and the other at higher speeds, allowing a constant maximum torque over a wide speed range, with a simple structure using few parts and low basic friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single braking gap design is used, then device complexity is reduced, but the ability to generate high torque across different speeds is limited
Solution Approach 1:
The braking device is segmented into multiple gap sections with different dimensions, allowing each section to be optimized for specific speed ranges. This segmentation provides versatility in torque generation across different operating conditions while maintaining a relatively simple overall structure that integrates all sections within a single braking assembly.
Solution Approach 2:
The braking device incorporates multiple gap sections that serve different functions: some sections are optimized for high torque at low speeds, while others are optimized for low friction at high speeds. This multi-functionality allows a single braking device to handle a wide range of operating conditions without requiring multiple separate braking systems, thus achieving versatility without proportionally increasing complexity.
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 device achieves a high maximum torque at different speeds with low basic friction, suitable for fine motor applications, and is cost-effective to produce, providing consistent haptic feedback without fatigue.
Implementation Method 1
If such a magnetorheological fluid is subjected to a magnetic field, the carbonyl iron particles of the magnetorheological fluid or the magnetorheological medium or the magnetorheological fluid link up along the magnetic field lines, so that the rheological properties of the magnetorheological medium are significantly influenced depending on the shape and strength of the magnetic field (transmissible shear stresses).
Implementation Method 2
At least one electrical coil wound around the axis of rotation and (radially) surrounding the core is accommodated between the casing part (shell portion) and the core
Data Source
AI summary
A haptic operating device having a magnetorheological braking device, a fixed holder, and two braking components. One braking component is non-rotatably connected to the fixed holder. Both braking components are continuously rotatable relative to one another about a rotation axis. A first braking component extends along a rotation axis and comprises a magnetically conductive core. The second braking component comprises a hollow casing part extending around the first braking component. At least one circumferential braking gap filled with a magnetorheological medium is between the first and second braking components. An electrical coil, surrounding the core and around the rotation axis, is between the casing part and the core. Two different radial braking gap portions and a disk contour are formed at a first braking gap portion between the casing part and the core, and a plurality of rolling bodies are arranged as magnetic field concentrators at the periphery of the core in a second braking gap portion.