Hydraulic Power Transmission Module for Lightweight Joint Assistance
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Solution Overview
Problem
Existing motion assistance devices for individuals with joint issues or for military applications lack efficient power transmission mechanisms that effectively convert and deliver power to assist movement while minimizing user effort and reducing device weight and size.
Innovation Solution
A power transmission module that includes a first transmission unit to receive rotary power, convert it to linear power, and deliver it to a joint assembly via a transfer agent, and an output power converter to convert linear power back to rotary power, with an output control device to adjust the rotary power delivered, allowing for efficient power transmission and assistance to joints like the ankle, knee, or hip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a power transmission mechanism is added to assist joint movement, then assistance to joints is improved, but device weight increases
Solution Approach 1:
The patent employs a hydraulic power transmission module where a first cylinder pressurizes a transfer agent (hydraulic fluid) to transmit power to a second cylinder. This hydraulic mechanism provides sufficient force assistance for joint movement while maintaining a compact and relatively lightweight structure compared to traditional mechanical power transmission systems.
2Force
If a power transmission mechanism is added to assist joint movement, then assistance to joints is improved, but device size increases
Solution Approach 1:
The patent integrates the power transmission module within the joint assembly structure, where the first and second cylinders are positioned to work together in a compact arrangement. The diaphragm and transfer agent system are nested within the cylinder bores, allowing the power transmission mechanism to fit within the existing joint assembly volume without significantly increasing overall device size.
Solution Approach 2:
Hydraulic systems are inherently more space-efficient than mechanical power transmission systems for providing equivalent force. The pressurized transfer agent transmits power through fluid pressure rather than requiring complex mechanical linkages, gears, or belts, thereby reducing the volume required for the power transmission mechanism.
3Reliability
If a diaphragm is added to prevent transfer agent contact with pressure rod, then reliability is improved, but device complexity increases
Solution Approach 1:
The diaphragm serves as an intermediary element between the transfer agent and the pressure rod. It allows the pressure rod to move freely within its cylinder while preventing direct contact with the transfer agent, thus maintaining system reliability without requiring complex sealing mechanisms or additional components.
Solution Approach 2:
The diaphragm is implemented as a flexible membrane that can deform to accommodate pressure rod movement while maintaining the barrier function. This thin-film approach provides effective isolation between the transfer agent and pressure rod with minimal addition to device complexity, as the diaphragm integrates seamlessly into the existing cylinder structure.
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 efficient power transmission and assistance to joints, reducing user effort and allowing for a slim, lightweight motion assistance device that can be worn discreetly, enhancing usability and reducing friction-related power loss.
Implementation Method 1
a first transmission unit (110) configured to pressurize a transfer agent to transmit power
Implementation Method 2
a diaphragm (112) configured to partition an inner space of the cylinder body and to prevent the transfer agent from contacting the pressure rod
Data Source
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AI summary
A power transmission device (100) comprising a first transmission (110) configured to receive a power from an input device (200); a second transmission (130) configured to deliver the power to an output device (500); and connecting unit (120) configured to connect the first power transmission unit and the second power transmission unit, and to deliver a pressure of a transfer fluid occurring due to the first power transmission unit to the second power transmission unit. A motion assistance device (10) comprising a driver (210) configured to mount to a user at a position corresponding to a proximal part of the user, and to generate a power; a joint assembly (400, 600) corresponding to a distal part of the user, the joint assembly configured to provide an assistance force to the user based on the power; and a power transmission device (100).