Projectile Ogive-Casing Multi-Start Threading for Simpler Assembly
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Solution Overview
Problem
The challenge in producing artillery projectiles lies in the complex and costly connection between the ogive and the projectile casing, requiring high-strength steels, precise machining, and stringent assembly processes due to the slim contour and high payload demands, which are exacerbated by spin acceleration and torque limitations.
Innovation Solution
A multi-start threaded profile connection is used to connect the ogive and projectile casing, featuring a large lead angle and multiple threads to reduce screwing forces and manufacturing complexity, eliminating the need for ultra-high-strength steels and simplifying assembly by reducing the need for bonding and friction coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If single-start fine threads are used to connect the ogive and projectile casing, then the connection can accommodate slim contours and high payload requirements, but the manufacturing complexity and cost increase due to required high-strength steels, precise machining, and stringent assembly processes
Solution Approach 1:
The patent changes the thread geometry parameters from single-start fine pitch to multi-start coarse pitch. This parameter change allows the same connection function to be achieved with different geometric characteristics, reducing the need for ultra-high-strength materials and simplifying manufacturing while maintaining structural integrity under spin acceleration loads.
Solution Approach 2:
The threaded connection is segmented into multiple starts rather than a single continuous thread. This segmentation allows each thread start to share the load, reducing the stress concentration and enabling the use of standard strength materials instead of ultra-high-strength steels, thereby simplifying the overall manufacturing process.
2Strength
If high-strength steels and bonding measures are used to ensure connection strength, then the connection can withstand spin acceleration, but the manufacturing effort and cost increase
Solution Approach 1:
The thread profile parameters are changed to multi-start coarse pitch geometry, which inherently distributes loads more effectively. This parameter change allows standard strength materials to achieve the required connection strength without needing ultra-high-strength steels, bonding agents, or friction coatings, significantly easing the manufacturing process.
Solution Approach 2:
The patent replaces expensive ultra-high-strength steels and complex bonding materials with standard strength materials and a simplified threaded connection design. This substitution reduces material costs and manufacturing complexity while maintaining sufficient connection strength for the application.
3Reliability
If tight manufacturing tolerances and friction coatings are applied to the threaded connection, then the connection prevents slippage during spin acceleration, but the production time and cost increase
Solution Approach 1:
The thread geometry is changed from fine pitch to coarse multi-start pitch, which provides inherent mechanical advantage and load distribution. This parameter change eliminates the need for tight manufacturing tolerances and friction coatings, as the threaded connection naturally prevents slippage under spin acceleration, thereby improving production efficiency.
Solution Approach 2:
The threaded connection design is self-reinforcing under operational loads. The multi-start coarse geometry automatically distributes and manages the forces during spin acceleration without requiring additional friction-enhancing treatments or tight tolerances, making the connection self-sufficient and simplifying production.
4Force
If ultra-high-strength steels are used for the threaded connection, then the necessary tightening torque can be achieved, but the material cost and machining complexity increase
Solution Approach 1:
The thread profile parameters are changed to multi-start coarse pitch, which provides mechanical advantage through increased lead angle. This parameter change allows standard strength materials to generate the necessary tightening torque and clamping force, eliminating the need for ultra-high-strength steels and reducing machining complexity.
Data Source
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AI summary
The invention relates to a projectile (1) with a projectile casing (2) and an ogive (4) mounted on the projectile casing (2), wherein the ogive (4) and the projectile casing (2) are connected to each other by a threaded profile connection (6), wherein the threaded profile connection (6) has several threads.