Linear Actuator Check Valve for Extension Arm Deaeration
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Solution Overview
Problem
In linear actuators, the pressure fluctuations between the extension arm and the housing lead to lubricating oil leakage from the second cavity into the first cavity, causing accumulation of oil in the first region which can restrict movement and lead to pressure peaks damaging the spindle piston.
Innovation Solution
A check valve is integrated between the first and second regions of the extension arm, allowing fluid to flow from the second region into the first region during retraction and preventing flow in the opposite direction, thus deaerating the extension arm and returning any leaked lubricating oil back to the second region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first region is completely sealed to prevent harmful factors, then reliability is improved, but pressure fluctuations cause lubricating oil to accumulate in the first region, leading to pressure peaks that damage the spindle piston
Solution Approach 1:
A check valve is introduced as an intermediary component between the first and second regions. This valve allows lubricating oil to pass from the second region to the first region during retraction, but prevents reverse flow during extension. The check valve mediates the pressure fluctuations by providing a controlled one-way flow path, preventing pressure peak formation while maintaining hermetic sealing of both regions.
Solution Approach 2:
The system changes the flow parameters of lubricating oil by using a check valve that responds to pressure differential changes. When pressure in the second region exceeds pressure in the first region during retraction, the valve opens to equalize pressure. When pressure conditions reverse during extension, the valve closes to maintain sealing. This dynamic parameter change enables the system to maintain hermetic sealing while preventing harmful pressure accumulation.
2Productivity
If the extension arm is rapidly retracted and extended, then productivity is improved, but pressure fluctuations overload the seals between the first and second regions
Solution Approach 1:
The check valve serves as a pressure equalization intermediary that activates during rapid movement cycles. During rapid retraction, it allows oil flow to compensate for volume changes, preventing excessive pressure buildup that would overload seals. During rapid extension, it maintains sealing integrity. This intermediary mechanism enables high-speed operation while protecting seal durability.
3Ease of operation
If lubricating oil flows through the threaded nut to enable movement, then ease of operation is improved, but the flow constriction drives oil into the second cavity causing accumulation
Solution Approach 1:
The check valve provides feedback-controlled oil flow management. During extension, it prevents oil from the first region from entering the second region, compensating for the oil that flowed through the threaded nut. During retraction, it allows oil to return to the first region, maintaining oil quantity balance. This feedback mechanism ensures continuous ease of operation while preventing harmful oil accumulation in the second cavity.
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 check valve ensures that the extension arm remains hermetically sealed while allowing the return of lubricating oil from the first region to the second region, preventing oil accumulation and pressure peaks, and maintaining the actuator's operational efficiency.
Implementation Method 1
If the threaded spindle extends, the pressure in this second region decreases. If it retracts, the pressure increases due to the displacement by the spindle.
Implementation Method 2
A check valve arranged between the first region and the second region in the piston allows fluid to pass in a first direction from the second region into the first region and blocks the passage of fluid in a second direction opposite the first.
Data Source
AI summary
An actuator includes a housing, an extension arm, and a threaded spindle. The threaded spindle is rotatably supported on the housing with respect to the center axis of the threaded spindle. The extension arm projects slidably out of the housing in the direction of the center axis. The housing and the extension arm together surround an interior space, whose volume changes as the extension arm moves. One end of the threaded spindle projects into a tubular portion of the extension arm, regardless of the position where the extension arm is located. The tubular portion extends about the central axis with a constant internal cross-sectional shape. The end of the threaded spindle is connected to a piston, which divides the internal space into a first region and a second region such that the first and second regions are separated from each other in a fluid-tight manner. The first region is only delimited by the piston and the extension arm. The second region is sealed against the environment in a fluid-tight manner. A check valve is arranged between the first region and the second region in the piston. The check valve passes fluid in a first direction from the second region to the first region of the extension arm and blocks the passage of fluid in a second direction opposite to the first.