MRF Brake and Reduction Gearbox for Aerospace Hydraulic Flow Control
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Solution Overview
Problem
Existing hydraulic fluid systems using magneto-rheological (MR) fluid are limited by compatibility with specific MR fluid properties, particularly in aerospace applications requiring recirculation without solid phase particles and low fluid density.
Innovation Solution
A hydraulic fluid system comprising a hydraulic motor, reduction gear box, and MRF brake, with separate housings and adjustable braking torque, controlled by a controller using magneto-rheological fluid to manage fluid flow and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magneto-rheological fluid is used to control hydraulic fluid flow, then fluid flow and pressure control is achieved, but the system requires solid phase particles and high density fluid which is incompatible with aerospace requirements
Solution Approach 1:
The patent introduces a reduction gear box as an intermediary mechanism between the hydraulic motor and MRF brake. This gear box with reduction ratio of 2:1 to 20:1 allows the use of a smaller, lighter MRF brake while achieving the same effective braking torque at the hydraulic motor output. The intermediary gear mechanism enables the system to meet aerospace weight and density requirements while maintaining precise flow control capability.
Solution Approach 2:
The patent changes the operating parameters by introducing a reduction gear box that modifies the torque and speed relationship between the hydraulic motor and MRF brake. By reducing the speed and increasing the torque through the gear box, the system can use a smaller MRF brake with less MRF fluid, thereby reducing overall system weight and fluid density while maintaining the same control effectiveness.
2Measurement precision
If a MRF brake is directly coupled to the hydraulic motor, then fluid flow control is achieved, but the system size and weight are excessive for aerospace applications
Solution Approach 1:
The reduction gear box serves as a mechanical intermediary that provides torque multiplication and speed reduction. This allows the MRF brake to be sized much smaller than it would need to be for direct coupling, since the gear box amplifies the braking torque effect at the hydraulic motor output. The intermediary mechanism decouples the size of the control device from the size of the actuator being controlled.
Solution Approach 2:
The system uses a planetary gear mechanism that provides dynamic torque multiplication. The reduction gear box with ratios of 2:1 to 20:1 dynamically adjusts the torque relationship between motor and brake, allowing the MRF brake to operate at lower torques while achieving the same effective braking effect at the motor shaft, thereby reducing brake and fluid quantity.
3Ease of operation
If MRF fluid with ferromagnetic particles is used, then magnetic control of fluid properties is achieved, but the fluid density becomes too high for aerospace recirculation requirements
Solution Approach 1:
The reduction gear box acts as a mechanical intermediary that reduces the amount of MRF fluid needed in the system. By providing torque multiplication, the gear box allows a smaller brake with less MRF fluid to achieve the same control effect, thereby reducing the total quantity of dense ferromagnetic fluid in the recirculation system.
Solution Approach 2:
The system changes the operational parameters by using a reduction gear box to reduce the torque requirement at the MRF brake. This parameter change allows the use of smaller brake components and less MRF fluid while maintaining the same magnetic control capability, effectively reducing the density-related burden on the hydraulic fluid recirculation system.
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
Enables precise control of hydraulic fluid flow and pressure, reducing system weight and size while maintaining performance, suitable for aerospace applications.
Implementation Method 1
A hydraulic fluid system is provided as defined by claim 1. In various embodiments, the hydraulic motor further includes an idler gear, and an output gear, where the output gear is coupled to the output shaft.
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A hydraulic fluid system is disclosed herein. The hydraulic fluid system includes a hydraulic motor (30) including an output shaft (42), a reduction gear box (45) having a first side and an opposing second side, the reduction gear box being coupled to the output shaft at the first side and coupled to a reduction shaft (43) at the second side, and a magneto-rheological fluid brake (MRF) brake (50) coupled to the reduction shaft.