Compliant-Slot Self-Locking Screw for Precise Bevel Gear Cutter Truing
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Solution Overview
Problem
Existing gear cutting tools for bevel gears face issues with cutting edge misalignment due to manufacturing tolerances and blade profile deviations, leading to loosening of adjustment screws during high-volume cutting, which causes vibrations and diminishes the effectiveness of radial blade truing, and existing lock spring designs require high pre-load torque that complicates precision adjustments and increases blade bending.
Innovation Solution
A self-locking screw with a high elasticity and self-locking torque, featuring a slotted design with an inserted elastic compliant sheet, providing a high self-locking torque of 5-10 Nm and maintaining the locking function through multiple cutter head cycles, while being inexpensive and easy to manufacture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lock spring design with pre-load is used to prevent adjustment screw loosening, then the screw loosening is prevented, but the total torque increases to 25 Nm or more making precision adjustment difficult and increasing blade bending
Solution Approach 1:
The patent changes the elastic modulus parameter of the slot material from rigid (metal) to compliant (elastic material with lower elastic modulus). This parameter change allows the slot to deform elastically under truing torque, absorbing the load without requiring high pre-load, thereby maintaining both reliability and ease of precision adjustment
Solution Approach 2:
The patent uses a composite structure combining rigid screw material with compliant slot material (elastic material). This composite approach allows the rigid screw to provide structural strength while the compliant material provides flexibility to accommodate adjustment torque without excessive pre-load, resolving the contradiction between locking reliability and adjustment precision
2Reliability
If a lock screw with closed slots is used to prevent loosening, then the locking effect is improved, but the spring constant becomes high and deflection amount becomes very small leading to plastic deformation
Solution Approach 1:
The patent changes the material parameter from rigid metal to compliant elastic material for the slot. This changes the mechanical properties allowing greater elastic deflection under load, preventing plastic deformation while maintaining the locking effect through the elastic recovery of the compliant material
Solution Approach 2:
The patent introduces dynamic elasticity to the slot, allowing it to flex and deform elastically under load rather than remaining rigid. This dynamic compliance enables the slot to absorb adjustment torques through elastic deformation and recover, preventing permanent plastic deformation while maintaining reliable locking
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 self-locking screw effectively prevents screw loosening during cutting operations, maintaining precision adjustments and reducing blade bending, with a controlled self-locking torque that supports high-precision adjustments without the need for excessive pre-load, thus enhancing the radial truing process.
Implementation Method 1
a self-locking screw (20) with a high elasticity and self-locking torque, featuring a slotted design with an inserted elastic compliant sheet
Implementation Method 2
The self-locking screw effectively prevents screw loosening during cutting operations, maintaining precision adjustments with a controlled self-locking torque
Data Source
AI summary
A self-locking screw wherein the self-locking function is maintained during many cutter head building and truing cycles. The inventive screw includes a self-locking feature having high elasticity and high self-locking torque. The screw includes a slot filled with an elastic compliant material.