Magnetorheological Actuator Structure for Thrust and Speed Control
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Solution Overview
Problem
Current actuation devices in machine tools, such as presses, face issues with non-constant reaction forces, limited control over rising steps, large space occupation, energy dissipation, and increased cycle times due to inefficiencies in pneumatic and hydraulic systems, and limitations of existing magnetorheological fluid solutions in terms of space and technical complexity.
Innovation Solution
A compact actuation device utilizing magnetorheological fluid with a jacket, tubular bushing, and electrical windings, featuring a telescopic stem and volume compensation chambers, allowing for modulation of thrust force and speed through controlled magnetic field exposure, and incorporating compressible or incompressible fluids for efficient energy management and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pneumatic cylinders are used for sheet presser actuation, then the device is simple and inexpensive, but the reaction force is not constant and increases during the pressing stroke, and large space is occupied
Solution Approach 1:
The patent replaces traditional pneumatic or hydraulic mechanical actuation systems with a magnetorheological fluid-based actuation system. The magnetorheological fluid's viscosity and flow characteristics are controlled by magnetic fields generated by electromagnetic coils, allowing precise control of reaction forces during the pressing stroke without the space requirements and force control limitations of pneumatic systems
Solution Approach 2:
The patent changes the physical parameters of the fluid system by using magnetorheological fluid whose rheological properties (viscosity, yield stress) can be dynamically adjusted through magnetic field strength. This allows the reaction force to be maintained constant or varied according to the pressing stroke requirements, resolving the force control issue while keeping the actuator compact
2Volume of stationary object
If hydraulic actuators are used for sheet presser actuation, then space occupation is reduced and pressure control is adequate, but relatively high costs and heat generation occur
Solution Approach 1:
The patent substitutes hydraulic actuators with a magnetorheological fluid actuation system that uses magnetic fields instead of hydraulic fluid flow. This eliminates the heat generation associated with hydraulic fluid laminar flow and pressure control while maintaining compact dimensions and adequate force control capability
Solution Approach 2:
The patent changes from incompressible hydraulic fluid to magnetorheological fluid whose properties can be adjusted via magnetic field parameters. This allows energy-efficient control of the sheet presser without the continuous energy dissipation and heat generation inherent in hydraulic systems
3Volume of stationary object
If nitrogen-filled cylinders are used, then space occupation is limited, but the same limitations as pneumatic cylinders remain regarding force control
Solution Approach 1:
The patent transforms the fixed-pressure gas system into a variable-property fluid system by using magnetorheological fluid. The magnetic field allows continuous adjustment of the fluid's rheological parameters, enabling force modulation during the pressing stroke while maintaining the compact cylinder design
Solution Approach 2:
The patent replaces the passive gas-pressure system with an actively controlled magnetorheological fluid system. The electromagnetic coils provide active control of the fluid properties, enabling precise force modulation that was impossible with passive nitrogen-filled cylinders
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 provides instantaneous control over thrust and speed, reduces energy dissipation, minimizes space occupation, and prevents dangerous energy releases, offering improved reliability and cost-effectiveness while effectively damping vibrations and managing eccentric loads.
Implementation Method 1
magnetorheological fluid (typically mineral oil with metal powder dispersion), in which the fluid changes its viscosity if it is subjected to a magnetic field
Implementation Method 2
electrical windings being present on the external wall of said bushing
Implementation Method 3
incorporating compressible or incompressible fluids for efficient energy management and heat dissipation
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
An actuation device (10, 110), of the type using magnetorheological fluid, which comprises at least the combination of: - a jacket (11, 111), - a tubular bushing (12, 112), which is internal to the jacket (11, 111) and is concentric thereto, electrical windings (13, 113) being present on the external wall of the bushing (12, 112), the jacket (11, 111) being closed at one end by an end plate (14, 114) and at the opposite end by a head (16, 116) which is perforated for the passage of - a first hollow stem (17, 117), adapted to protrude from the head (16, 116) by translating on - a second hollow stem (18, 118), which extends from the end plate (14, 114) inside the bushing (12, 112), - an annular element (19, 119), which is integral with the first hollow stem (17, 117) and translates with it inside the bushing (12, 112), - a first chamber (20, 120), adapted to contain the magnetorheological fluid, - a second chamber (21, 121), in fluidic connection with the first chamber (20, 120) by means of an interspace (22, 122) between the bushing (12, 112) and the jacket (11, 111), - a third volume compensation chamber (23, 123).