Linear Actuator Friction Spring Damping for End-of-Stroke Impact
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional linear actuators, particularly electric and hydraulic ones, face challenges in damping at the ends of the actuator stroke due to high inertial mass and force, leading to undesirable jarring and wear, as hydraulic damping techniques are not applicable and electric actuators require complex feedback loops for effective damping.
Innovation Solution
Incorporation of friction springs, such as Ringfeder friction springs, at the ends of the axially moveable member to absorb impact and energy, providing effective damping without the need for hydraulic systems and complex feedback loops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic damping techniques are used, then damping effect is improved, but device complexity and inapplicability to electric actuators worsen
Solution Approach 1:
The patent extracts the damping function from the complex hydraulic system and implements it through a simple mechanical friction spring mechanism. The friction spring is directly mounted on the axially moveable member, eliminating the need for hydraulic fluid, valves, and complex control systems while providing effective damping at the ends of the stroke.
Solution Approach 2:
The patent replaces the hydraulic damping system with a purely mechanical friction spring mechanism. The friction spring provides damping forces through friction and elastic deformation, substituting the need for hydraulic fluid compression and flow control, making it applicable to both electric and hydraulic actuators.
2Ease of repair
If electric actuators are used, then maintenance requirements are reduced, but inertial mass and damping requirements worsen
Solution Approach 1:
The friction spring is pre-installed on the axially moveable member to provide cushioning before impact occurs. As the actuator approaches the end of its stroke, the friction spring engages and gradually absorbs kinetic energy through friction and elastic deformation, preventing sudden impact and reducing wear on the actuator components.
3Object-affected harmful factors
If feedback loops are used for electric slowing, then impact reduction is improved, but device complexity and reliability worsen
Solution Approach 1:
The friction spring mechanism is self-regulating and does not require external control systems. As the axially moveable member moves, the friction spring automatically engages and provides damping forces based on the relative motion and load, eliminating the need for sensors, feedback loops, and complex control algorithms.
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 friction springs effectively absorb kinetic energy and reduce wear by providing consistent damping, enhancing the reliability and safety of linear actuators while maintaining a compact design.
Implementation Method 1
The springs are in the form of friction springs such as those available under the mark 'Ringfeder' friction springs
Implementation Method 2
a spring is mounted at each end of the axially moveable member... to absorb impact and energy
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A linear actuator comprising: an axially moveable member (1); a housing (2) within which the axially moveable member is mounted for linear movement relative to the housing; drive means (5) to move the axially moveable member between an extended axial position and a retracted axial position; and one or more springs (8) provided to absorb impact from axial movement of the axially moveable member at the extended axial position and/or at the retracted axial position.