Orthopedic Actuator Heat Store for Longer High-Load Operation
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Solution Overview
Problem
Orthopedic devices face challenges in maintaining extended operating times at high loads due to low heat storage capacity, which results in severe heating and reduced performance.
Innovation Solution
An actuator system is developed that includes a heat store with a housing and a heat storage medium, allowing for increased thermal capacity by separating the mechanical and dynamic requirements from the heat storage requirements, thus optimizing both mechanics and heat storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the actuator is designed to be lightweight and compact, then the weight and volume are reduced, but the heat storage capacity becomes insufficient
Solution Approach 1:
The actuator system is divided into two independent modules: the actuator housing containing mechanical components, and a separate heat store housing containing the heat storage medium. This segmentation allows each module to be optimized independently - the actuator for mechanical performance and the heat store for thermal capacity - resolving the contradiction between lightweight design and heat storage capacity.
Solution Approach 2:
The heat store housing is designed to be mounted on the actuator housing, with the heat store receiving region positioned to surround or adjacent to the actuator housing. This nested arrangement allows the heat storage medium to be in thermal contact with the actuator components without significantly increasing the overall volume, thus increasing heat storage capacity while maintaining a compact form factor.
2Duration of action of moving object
If the heat storage capacity is increased to extend operating time, then the operating duration is improved, but the volume and weight increase
Solution Approach 1:
The heat storage medium is positioned in specific locations where it can most effectively absorb heat from the actuator components, such as surrounding the motor housing or hydraulic cylinder. The heat store housing is configured with a receiving region that provides optimal thermal contact with the actuator housing, ensuring efficient heat transfer while minimizing the volume occupied by the heat storage system.
3Power
If the actuator components are operated at their limits to increase power output, then the power is improved, but the temperature rises severely
Solution Approach 1:
The heat storage medium acts as a thermal intermediary between the actuator components and the environment. It absorbs excess heat generated during high-power operation through thermal conduction from the actuator housing, preventing the actuator components from overheating. This allows the actuator to operate at higher power levels for extended periods without exceeding temperature limits.
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 extends operating times at high loads by delaying the rise in operating temperature and smoothing dissipative power peaks, while maintaining a lightweight and compact design.
Implementation Method 1
a heat store for storing the heat produced during operation of the actuator
Implementation Method 2
increase the thermal capacity of the actuator
Implementation Method 3
which, in the installed state of the heat store, is in heat-transferring contact with the actuator housing
Implementation Method 4
an increase in the heat storage capacity slows down cooling, and the peaks in the dissipative power of the actuator are smoothed
Data Source
AI summary
The invention relates to an actuator for an orthopedic device with an actuator housing and a heat store for storing the heat produced during operation of the actuator, the heat store having a heat store housing that has a cavity and a heat storage medium present therein, or consisting of a heat storage medium. The heat store is designed to be attachable to or in the actuator housing and has a receiving region that matches an actuator housing region and, when the heat store is mounted, is in heat-transferring contact with the actuator housing.