Projectile Bearing System with Conical Surfaces and Spring Biasing
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Solution Overview
Problem
Existing bearing systems for spin-stabilized and fin-stabilized projectiles face challenges in withstanding excessive launch loads while maintaining lightweight and low-drag characteristics, which are essential for stability and on-target delivery, as they need to survive set-back, balloting, and in-flight loads effectively.
Innovation Solution
A bearing system featuring rotationally complementary conical mating surfaces and spring-biased elements that automatically re-center the spindle, allowing relative rotation and distributing loads to prevent deformation, thereby isolating bearings from overloads and redirecting radial forces into axial motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional bearing systems are used to withstand launch loads, then reliability is improved, but weight increases and drag increases
Solution Approach 1:
The bearing system transitions from a static load-bearing structure to a dynamic system where the spindle can move axially and radially relative to the bearing members during launch, then returns to a centered rotational position during flight. This dynamic behavior allows the same bearing components to handle both extreme launch loads and precise in-flight rotational requirements without requiring over-engineered static structures.
Solution Approach 2:
The patent changes the operational parameters of the bearing system by allowing axial and radial displacement of the spindle during launch, then returning to a centered position for flight. The bearing members are designed to accommodate these parameter changes, switching between load-bearing and precision rotational functions based on the flight phase, thereby reducing overall bearing weight while maintaining reliability.
2Reliability
If bearing size is increased to handle launch loads, then reliability is improved, but in-flight performance deteriorates due to increased drag and weight
Solution Approach 1:
The bearing system is designed to be dynamic rather than static, allowing the spindle to displace during launch and return to a centered position during flight. This dynamic capability enables the bearing components to be optimized for both phases: sufficient size to handle launch loads when needed, but not permanently oversized which would increase drag and affect in-flight stability.
Solution Approach 2:
The bearing system automatically adjusts its configuration based on operational phase through spring-biased re-centering mechanisms. During launch, the system accommodates large displacements; during flight, the springs automatically return components to their optimal centered positions, eliminating the need for manual adjustment or oversized fixed components that would degrade in-flight performance.
3Weight of moving object
If lightweight bearings are used to reduce projectile weight, then in-flight stability is improved, but ability to withstand launch loads deteriorates
Solution Approach 1:
The lightweight bearing system compensates for reduced load-bearing capacity through dynamic displacement during launch. Instead of relying on heavy static structures, the system allows axial and radial movement of the spindle, distributing launch loads across multiple bearing members and the launch tube structure, then returns to precise centered rotation during flight for stability.
Solution Approach 2:
The patent merges the functions of multiple bearing members (front and rear bearing assemblies with inner and outer members) to collectively handle launch loads that would be too heavy for a single bearing. This distributed load-bearing approach reduces individual component weight while maintaining overall launch load resistance through coordinated operation of multiple lighter elements.
4Reliability
If bearing system allows radial movement during launch, then launch load survival is improved, but in-flight centering precision deteriorates
Solution Approach 1:
The bearing system employs dynamic radial and axial displacement during launch to survive extreme loads, then utilizes spring-biased re-centering mechanisms to automatically return the spindle to precise centered position during flight. This dynamic transition from flexible load-bearing to precise centering maintains both launch survival capability and in-flight rotational accuracy.
Solution Approach 2:
The spring-biased bearing members provide a feedback mechanism that automatically detects spindle displacement during launch and generates restoring forces to return the spindle to its centered position during flight. This passive feedback system ensures that after experiencing radial and axial loads during launch, the bearing system self-corrects to achieve the precise centering required for stable in-flight rotation.
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 protects bearings from launch overloads, maintains lightweight and low-drag characteristics, and ensures accurate re-centering and stability during flight, enhancing the projectile's stability and guidance capabilities.
Implementation Method 1
Respective biasing means may be provided to axially bias the cooperating member towards the respective first and second members
Implementation Method 2
rotationally complementary bearing surface interfaces, such as conical, concave-convex, etc. interfaces for a rotatable spindle that transfer launch (set-back, set-forward, balloting), and pre-launch and/or in-flight equilibrium loads
Data Source
Figure 1
Figure 2
Figure 2A~2B
AI summary
A bearing system for a spin-stabilized projectile (P) including bearing configurations (20,36) that permit selective relative rotation between a spindle (18) and a body portion (14) and which facilitate automatic centering of the spindle (18). Each bearing configuration (20,36) includes a conical bearing surface rotatable with respect to a corresponding conical body surface. One bearing configuration (20) is in a forward portion of the body portion and selectively engages a first body surface upon the projectile experiencing set-back forces to direct forces away from bearing elements, and another bearing configuration (36) is in a rearward portion of the body portion and engages a second body surface upon the projectile experiencing set-forward forces to direct forces away from the bearing elements. Biasing elements work in cooperation with the bearing configurations (20,36) to automatically maintain the spindle (18) centered with respect to the body portion (14) during pre-launch and in-flight and to re-center the spindle after set-back, balloting and/or set-forward phases.