Conical Insert Spindle Coupling to Prevent Tool Structure Breakage
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Solution Overview
Problem
Existing tools with inserts for working on hard and abrasive surfaces face structural breakage due to stress from the insert, particularly from the circular hole designed to contain the insert, under thermal expansion and interference fitting.
Innovation Solution
A system with a conical containment hole and spindle, where the spindle is designed to be inserted by exploiting thermal expansion differences, allowing for secure coupling without radial load interference, thus preventing structural breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a circular hole is used to contain the insert, then the insert can be held in place, but the structure breaks due to stress from the insert under thermal expansion and interference fitting
Solution Approach 1:
The patent changes the circular containment hole to a conical shape, creating an asymmetric geometry that distributes stress more effectively. The conical form allows the insert to be held securely while reducing stress concentration points that cause structural failure under thermal expansion and interference fitting conditions.
Solution Approach 2:
The patent modifies the geometric parameters of the containment hole from a standard circular cross-section to a conical configuration with specific angle and dimension ratios. This parameter change optimizes the stress distribution and thermal expansion accommodation, preventing structural breakage while maintaining insert retention.
2Strength
If the insert is made of tungsten alloy with high hardness, then wear resistance is improved, but thermal expansion causes interference fitting problems
Solution Approach 1:
The patent explicitly accounts for thermal expansion by designing the conical containment hole with specific geometric parameters that accommodate the differential thermal expansion between the tungsten alloy insert and the steel tool body. The conical geometry allows for controlled expansion without creating excessive interference fitting stresses that would cause structural failure.
3Productivity
If the insert protrudes from the tool, then the tool remains sharp and breaking factor increases, but the structure cannot guarantee support of the insert
Solution Approach 1:
The conical containment hole creates an asymmetric support structure that effectively holds the protruding insert. The tapered geometry provides gradual stress distribution along the insert length, enabling the insert to protrude for optimal working performance while the conical structure maintains reliable structural support.
Solution Approach 2:
The conical shape introduces curved surfaces that distribute loads more effectively compared to a cylindrical hole. The curved geometry of the conical containment hole provides better stress distribution and support for the protruding insert, preventing structural failure while maintaining the necessary breaking factor.
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 system effectively secures the insert within the tool structure without causing structural breakage, ensuring prolonged tool life and stability during operations on hard and abrasive surfaces.
Implementation Method 1
The spindle (7) is designed to be inserted in the containment hole (5) by exploiting thermal expansion differences
Data Source
AI summary
A system (1) for working hard and abrasive surfaces is provided. The system has a support and containment structure (3) equipped with a containment hole (5), and a spindle (7) to be inserted in the containment hole (5). The spindle is elongated and has a conical section with a first diameter (A) oriented towards the outside of the structure (1) and a second diameter (B) greater than the first diameter (A) and oriented towards the inside of the structure (1) and a conical section with a third diameter (A′) oriented towards the outside of the structure (1) and a fourth diameter (B′) greater than the first diameter (A′) and oriented towards the inside the structure (1). the spindle (7) is inserted into the containment hole (5) by raising or reducing the temperature of the support and containment structure (3).