Offset Journal Shoes for Misalignment Without Lubricant Scraping
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Solution Overview
Problem
Mechanical systems with misaligned or worn components in linear motion transmission experience inefficiencies due to force concentration, lubrication failure, and premature wear, particularly in applications like chuck and return cam systems.
Innovation Solution
A device with a cylindrical journal having symmetrical shoes with offset centers of rotation, allowing lubrication by rotating away from the contact edge, ensuring optimal lubrication and compensating for misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a cylindrical shoe contacts with the ramp via a flattened surface to compensate for misalignment, then the adaptability to misalignment is improved, but the shoe rotates in the direction of sliding causing lubricant scraping and lubrication failure
Solution Approach 1:
The patent applies asymmetry by offsetting the center of rotation of the cylindrical shoe from the center of the flattened contact surface. This asymmetric configuration creates a moment that counteracts the rotation caused by sliding friction, allowing the shoe to maintain proper orientation and prevent lubricant scraping while still adapting to misalignment.
Solution Approach 2:
The patent changes the geometric parameter of the shoe by introducing an offset between the center of rotation and the center of the flattened surface. This parameter modification fundamentally alters the shoe's rotational behavior during sliding, transforming it from a harmful rotation that scrapes lubricant to a controlled motion that maintains lubrication.
2Stability of the object's composition
If the shoe is allowed to rotate to maintain contact with the ramp, then the contact stability is improved, but the leading or following edge faces the lubricant and scrapes it off
Solution Approach 1:
The asymmetric offset between the center of rotation and the flattened surface center creates a stabilizing moment that prevents the shoe from rotating into a position where edges scrape the lubricant. The shoe maintains stable contact while the offset geometry ensures the contact surface remains properly oriented.
Solution Approach 2:
The patent converts the harmful effect of friction-induced rotation into a beneficial effect. The offset center of rotation uses the friction force to create a moment that actually prevents harmful rotation, transforming the potential harm into a stabilizing mechanism that protects the lubrication film.
3Device complexity
If misalignment is not compensated, then the device complexity is reduced, but force concentration on edges causes premature wear and system failure
Solution Approach 1:
The patent introduces dynamic adaptability by allowing the cylindrical shoe to rotate about an offset center. This dynamic capability enables the shoe to automatically adjust to misalignment conditions, distributing forces evenly and preventing edge concentration without requiring complex adjustment mechanisms.
Solution Approach 2:
By modifying the geometric parameter (offset center of rotation), the patent enables the simple shoe structure to dynamically adapt to misalignment, maintaining reliability without increasing overall device complexity. The offset parameter provides inherent compensation capability.
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
Enhances lubrication and mechanical efficiency by preventing lubricant scraping, reducing wear, and maintaining system functionality despite misalignment.
Implementation Method 1
due to the friction of the ramp on the flattened surface of the shoe, the latter tended to rotate in the direction of the sliding, such that its leading or following edge is facing the lubricant and scraping it off
Data Source
AI summary
A device for transmitting a movement between a first member and a second member, namely from a driving member to a driven member, of the type having a cylindrical journal with a circular base mounted so as to rotate in a recess of the driven member or of the driving member. At least one of the ends of this journal is hollowed out by a groove capable of forming, on either side thereof, two shoes that are symmetrical with respect to an axial and diametral plane of the journal and capable of engaging, by a flattened surface, with the driving member or the driven member, the cross-section of each shoe being delimited by an arc of a circle matching the external surface of the journal, ending in a line segment that is part of the flattened surface.