Feed Screw Mechanism Uniform Load Distribution
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Solution Overview
Problem
The existing feed screw mechanisms experience non-uniform load distribution on the tooth flanks of externally and internally threaded members, leading to durability issues and impaired smooth operation due to uneven contact surface pressure during load application.
Innovation Solution
The internally threaded member is coupled to the output rod via a threadedly meshing coupling portion at its axial end, preventing compression loads from being applied to the internally threaded member during contraction, ensuring that both members receive uniform loads along the axis, thus distributing pulling loads equally to both members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the internally threaded member is fixed within the output rod using conventional means, then the output rod can be formed of iron to ensure strength, but non-uniform load distribution occurs on the tooth flanks of the threaded members
Solution Approach 1:
The internally threaded member is segmented from the output rod through the use of a coupling portion with internal threads that engage with external threads on the internally threaded member. This segmentation allows the internally threaded member to be freely fitted within the output rod, enabling uniform load distribution on the tooth flanks while maintaining the strength of the iron output rod.
2Ease of manufacture
If the internally threaded member is integrally formed with the output rod, then manufacturing is simplified, but the output rod cannot be formed of iron when the internally threaded member is made of bronze or aluminum
Solution Approach 1:
The internally threaded member made of bronze or aluminum is nested within the hollow iron output rod. The coupling portion with engaging threads provides the necessary connection, allowing different materials to be combined - the iron output rod provides strength while the bronze or aluminum internally threaded member provides appropriate threading properties.
3Device complexity
If compression load is applied to the internally threaded member during contraction, then the feed screw mechanism can be compact, but non-uniform transmitted load occurs on the tooth flanks
Solution Approach 1:
The coupling portion acts as an intermediary between the output rod and the internally threaded member. Through the engagement of internal threads on the coupling portion with external threads on the internally threaded member, pulling loads can be applied uniformly to both members without subjecting the internally threaded member to compression loads, ensuring uniform transmitted load distribution.
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 configuration enhances the durability and smooth operation of the feed screw mechanism by maintaining uniform load distribution on the tooth flanks, preventing abnormal wear and ensuring consistent relative rotation.
Implementation Method 1
an externally threaded member (95) which is adapted to be rotated about an axis L by a drive source (36), and an internally threaded member (96) which is adapted to be engaged with the externally threaded member (95), wherein the internally threaded member (96) is freely fitted within a hollow output rod (33)
Data Source
AI summary
A feed screw mechanism includes internally threaded member fixed within an output rod. The internally threaded member is threadedly engaged with an externally threaded member connected at axially one end in the direction of an axis thereof to a drive source, so that the output rod is moved in a direction of the axis relative to the externally threaded member by the relative rotation of the externally threaded member and the internally threaded member. The internally threaded member is coupled to the output rod at the axially other end in the direction of the axis by a threadedly coupling portion. Therefore, when pulling loads in directions away from each other are applied to the output rod and the externally threaded member, a compression load can be prevented from being applied from the output rod to the internally threaded member.