Cardan Joint Bearing Layout for Shock-Resistant Payload Stabilization

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Solution Overview

Problem

Current cardan joints used for stabilizing imaging and sensing devices on moving systems are limited by their load-carrying capacity and prone to failure under dynamic shock loads and vibrations, and lack integral angle measurement systems to track movement and displacement.

Innovation Solution

A cardan joint design incorporating a cross-elevation assembly, roll-elevation assembly, and payload interface assembly with radial and thrust roller bearings, along with an integral angle measurement system using positioning targets and sensors, which allows for inertial stabilization and measurement of rotational movement across multiple axes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If angular contact bearing or flexure element is used in cardan joint, then device isolation from movement is achieved, but load carrying capacity is limited and failure risk increases under dynamic shock loads

Engineering Contradiction:

Improvecardan joint reliabilityVSAvoidload carrying capacity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The cardan joint is divided into multiple independent bearing assemblies, each handling specific load components. Multiple roller bearings are distributed across different locations and orientations to collectively support radial, axial, and moment loads, preventing any single bearing from being overloaded during dynamic shock events

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different bearing types and configurations are used at different locations within the cardan joint to optimize local load handling. Roller bearings with specific contact angles and arrangements are placed at critical positions to address the particular stress conditions experienced at each location, enhancing overall joint reliability

Inventive Principle:

Principle #3Local quality

2Reliability

If angular contact bearing or flexure element is used in cardan joint, then device isolation from movement is achieved, but cardan joint size increases beyond desirable limits

Engineering Contradiction:

Improvecardan joint reliabilityVSAvoidcardan joint volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

Multiple bearing assemblies are arranged in a nested or compact configuration where components are positioned within the spatial envelope of others. The roller bearings are distributed throughout the cardan joint structure, utilizing available space efficiently to provide comprehensive load support without increasing the overall joint volume

Inventive Principle:

Principle #7Nested doll (Nesting)

3Ease of operation

If current cardan joint design is used, then basic stabilization is provided, but angle measurement and displacement tracking are not available

Engineering Contradiction:

Improvestabilization functionVSAvoidangle measurement capability

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The cardan joint structure serves multiple functions simultaneously: it provides mechanical stabilization through the bearing assemblies while also incorporating integrated sensors and measurement systems that enable precise angle and displacement tracking. The same structural components that provide mechanical support also serve as mounting platforms for measurement instrumentation

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Enhances load-carrying capacity, reduces the risk of failure, and enables precise measurement and stabilization of payloads, allowing for stable imaging and sensing even under dynamic conditions.

Implementation Method 1

A cardan joint design incorporating a cross-elevation assembly, roll-elevation assembly, and payload interface assembly with radial and thrust roller bearings

Methodology Applied

Scientific EffectRoller bearing: Ball Bearing

Data Source

PatentUS11243082B2Cardan joint for inertially stabilizing a payload

Publication Date: 2022.02.08 RAYTHEON CO

AI summary

A cardan joint includes a cross-elevation assembly comprising a cross-elevation housing, a roll-elevation assembly comprising a roll-elevation housing, a payload interface assembly comprising a payload interface housing, and a suspension interface yoke comprising a suspension interface that couples the suspension interface yoke to one or more suspension bars. The roll-elevation assembly is rotatably connected to the cross-elevation assembly along a first rotation axis via a radial roller bearing and a thrust roller bearing. The payload interface assembly is rotatably connected to the roll-elevation assembly along a second rotation axis via a radial roller bearing and a thrust roller bearing. The suspension interface yoke is rotatably connected to the cross-elevation assembly along a third rotation axis via one or more radial roller bearings and one or more thrust roller bearings. The payload interface housing comprises a payload interface operable to couple the payload interface housing to an inertially stabilized payload.