Integrated Angular Contact Bearing Preload for Rocket Guidance Stiffness

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Solution Overview

Problem

Existing guidance mechanisms for attack rockets face a trade-off between achieving lightweight, high stiffness, and low rolling friction torque, which is essential for maintaining a steady flight course while minimizing power consumption, as multiple bearings and retainer nuts increase weight and cost.

Innovation Solution

The design incorporates a pair of angular contact bearings with a single retaining nut to preload both bearings, reducing the number of components and optimizing preload distribution for maximum stiffness and minimal torque, using a combination of annular housings and shoulders to achieve a lightweight, high-stiffness configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If multiple pairs of angular contact ball bearings and retainer nuts are used to stiffen the guidance mechanism, then system stiffness is improved, but device complexity and weight increase

Engineering Contradiction:

Improvesystem stiffnessVSAvoidnumber of bearings and retainer nuts

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent combines multiple bearing support functions into a single duplex bearing assembly with integrated preload features. The inner and outer bearings are pre-assembled with spacers and retainer nuts in a unified structure, reducing the total component count while maintaining the required stiffness through optimized bearing configuration and preload distribution.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The guidance mechanism is segmented into modular bearing assemblies that can be pre-configured and tested independently before final installation. Each duplex bearing assembly functions as a self-contained module with integrated preload elements, allowing for simplified assembly and replacement while maintaining system stiffness requirements.

Inventive Principle:

Principle #1Segmentation

2Stability of the object's composition

If multiple pairs of angular contact ball bearings are used to increase system stiffness, then bearing capacity is improved, but weight increases requiring heavier motors and components

Engineering Contradiction:

Improvesystem stiffnessVSAvoidguidance mechanism weight

Core Design Contradiction:

Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

Multiple bearing functions are merged into compact duplex assemblies where inner and outer bearings share common mounting structures and preload elements. This integration reduces the total weight compared to using separate bearing assemblies while maintaining the cumulative stiffness benefit of multiple bearings working together.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If traditional bearing assemblies with multiple retainer nuts are used, then bearing preload is achieved, but manufacturing cost and assembly complexity increase

Engineering Contradiction:

Improvebearing preloadVSAvoidmanufacturing cost and assembly complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Multiple retainer nuts that traditionally required separate installation are merged into a single integrated retainer nut assembly for each duplex bearing. This unified structure allows all bearing preload adjustments to be made through one component, significantly simplifying the manufacturing and assembly processes while ensuring proper preload is applied to both inner and outer bearings.

Inventive Principle:

Principle #5Merging (Combining)

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 rocket's resistance to shock and vibration, reduces power requirements, and provides a more efficient guidance mechanism with improved manufacturability and assembly precision, achieving over 200% increase in moment stiffness compared to traditional designs while minimizing weight and component count.

Implementation Method 1

minimum rolling friction torque

Methodology Applied

Scientific EffectRolling friction: Friction

Implementation Method 2

the retaining nut preloading the first and second angular contact bearings

Methodology Applied

Scientific EffectMechanical preload: Mechanical Force

Data Source

PatentUS9453531B2Integrated bearing assemblies for guided attack rockets

Publication Date: 2016.09.27 ROLLER BEARING OF AMERICA INC

AI summary

A guide mechanism, configured for use with a guided attack rocket, includes an inner housing partially disposed in an outer housing. The inner and outer housings each define a forward end and an aft end. A first angular contact bearing is positioned between the outer housing forward end and the inner housing forward end. A second angular contact bearing is positioned between the outer housing aft end and the inner housing aft end. A retaining nut is received over the inner housing forward end. The retaining nut preloads the first and second angular contact bearings. Each of the angular contact bearings includes an inner member disposed within an outer member. The outer member defines an outer raceway and the inner member defines an inner raceway. A plurality of rolling elements is disposed between the outer raceway and the inner raceway.