Ballscrew Lubrication Pump Using Pressure-Differential Replenishment
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Solution Overview
Problem
Ballscrew actuators require frequent manual replenishment of lubricant, which is costly and inefficient, as lubricant escapes from the interface between the ballscrew and ballnut due to inadequate sealing.
Innovation Solution
A lubrication system with a reservoir, pump, and pressure differential mechanism using a piston with two cavities and non-return valves to automatically supply lubricant to the interface between the ballscrew and ballnut, utilizing ambient or aircraft pressure differences to facilitate lubricant delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual lubricant replenishment is performed at regular intervals, then the lubrication system maintains adequate lubrication, but maintenance cost and operational downtime increase
Solution Approach 1:
The system employs a self-regulating lubrication mechanism where a piston automatically dispenses lubricant from the reservoir to the interface between the ballscrew and ballnut based on pressure differential, eliminating the need for manual intervention and achieving continuous self-maintenance
Solution Approach 2:
The lubricant is pre-stored in a reservoir, and the piston mechanism is pre-configured to automatically dispense lubricant when pressure conditions are met, ensuring lubrication is replenished before complete depletion occurs without requiring operational shutdown
2Extent of automation
If a piston mechanism with pressure differential is used to automatically supply lubricant, then manual replenishment frequency decreases, but device complexity increases
Solution Approach 1:
The system utilizes pressure differential (pneumatic principle) to drive the piston mechanism, where pressure changes in the first and second cavities automatically control piston movement and lubricant dispensing without requiring complex electronic controls or additional actuators
Solution Approach 2:
The piston serves multiple functions: it acts as a seal between the reservoir and interface, a pump mechanism for lubricant delivery, and a pressure-regulated valve, thereby reducing the need for separate components and simplifying the overall system architecture
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
Reduces the need for manual lubricant replenishment, ensuring continuous lubrication and prolonged service life of the actuator by automatically replenishing lubricant, thereby minimizing maintenance and maintaining corrosion resistance.
Implementation Method 1
The first cavity and second cavity are placeable in fluid communication with one or more pressure sources externally of the pumping chamber so as to provide a pressure differential between the first cavity and the second cavity, whereby the piston may move as a result of the pressure differential
Implementation Method 2
a first cavity non-return valve may be provided in fluid communication with the first cavity. The first cavity non-return valve may be configured to allow venting of fluid out from the first cavity as a pressure outside of the pumping chamber falls, but to prevent admission of fluid into the first cavity as a pressure outside of the pumping chamber rises
Data Source
AI summary
A lubrication system comprises a lubricant reservoir, a lubricant supply passage fluidly connecting the lubricant reservoir and a space requiring lubrication, and a lubricant supply pump. The supply pump includes a piston having a first piston head slidably received in a chamber in fluid communication with the lubricant reservoir and a second piston head slidably received in a pumping chamber. The pumping chamber is divided into a first and second cavities by the second piston head. The first cavity is between the first piston head and second piston head. The first and second cavities are placeable in fluid communication with pressure sources externally of the pumping chamber to provide a pressure differential between the first cavity and the second cavity, whereby the piston may move as a result of the pressure differential to cause the first piston head to dispense lubricant from the lubricant reservoir to the space.