Eccentric Bore Ventilation for Telescopic Shaft Lubricant Clogging
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Solution Overview
Problem
The ventilation opening in adjustable-length shafts becomes blocked due to lubricant buildup, as lubricant vapors condense and collect in the ventilation opening, leading to air compression and subsequent clogging.
Innovation Solution
The ventilation opening is designed with at least one bore that has a longitudinal axis offset eccentrically or radially to the shaft's axis of rotation, allowing lubricant deposition only on the outer area, preventing a closed lubricant ring and enabling lubricant to flow out into the inner cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ventilation opening is provided in the front wall to establish conductive connection between cavities, then air compression damping effect is achieved when shaft is shortened, but lubricant vapors condense and plug the ventilation opening over time
Solution Approach 1:
The bore's longitudinal axis is positioned eccentrically relative to the shaft's axis of rotation, creating an asymmetric configuration. This asymmetry ensures that during rotation, lubricant deposits only on the radially outer area of the bore while the radially inner area remains clear, preventing complete blockage of the ventilation opening
Solution Approach 2:
The solution introduces a spatial dimension consideration by offsetting the bore axis radially from the shaft rotation axis. This dimensional offset creates a three-dimensional arrangement where lubricant deposition is confined to a specific radial zone, leaving alternative pathways open for ventilation function
2Length of moving object
If the shaft is shortened by pushing the inner axial part into the outer axial part, then length adjustment is achieved, but air is compressed in the cavity causing lubricant vapor condensation
Solution Approach 1:
The eccentric bore design converts the harmful effect of lubricant deposition into a beneficial pattern where condensation is directed to specific areas. The lubricant that would normally block the opening is channeled to deposit only on the outer radial area, while the inner area remains clear for ventilation, thus converting a blocking problem into a directed deposition solution
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
This design prevents the ventilation opening from becoming blocked for an extended period, ensuring that lubricant does not cause damage by flowing out of the bore into the inner axial part's cavity.
Implementation Method 1
lubricant vapors collect in the space enclosed by the outer axial part and condense in the ventilation opening
Implementation Method 2
due to the eccentricity of the longitudinal axis of the bore relative to the axis of rotation of the shaft, lubricant is only deposited in the radially outer area of the bore
Data Source
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AI summary
The invention relates to a length-adjustable shaft comprising - an outer sleeve-shaped axial part; - an inner axial part which can be pushed into and deployed out of the outer axial part in a telescopic fashion and which encloses a buffer chamber; - having a bearing which is arranged between the two axial parts and which can be lubricated with a lubricant; - that end of the inner axial part which can be pushed into the outer axial part has an end wall; - a ventilation opening is provided which connects, in a conducting fashion, the buffer chamber to the cavity which is enclosed by the outer axial part. The invention is characterized by the following features: the ventilation opening comprises at least one bore which is offset with respect to the rotational axis of the shaft.