Rolling Element Pendulum Bearing for Gyrocompass

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Solution Overview

Problem

Gyro compass systems experience course errors due to sluggishness in pendulum joint bearings, vertical errors, and the stick-slip effect, leading to asymmetric bearing and friction issues, which affect the accuracy and reliability of course display.

Innovation Solution

A rolling element self-aligning bearing with a part-spherical rotary body and hollow body design, featuring a large contact angle to reduce friction, allowing for simultaneous rotary and pivot mounting, and incorporating a cage to guide rolling elements and absorb bearing forces, thereby minimizing the stick-slip effect and improving plumbness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple ball bearing with plain bearing surfaces is used, then the device complexity is low, but the friction increases leading to stick-slip effect and course errors

Engineering Contradiction:
Improvebearing structure complexityVSAvoidcourse display accuracy
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Rolling elements (balls or rollers) are introduced as intermediary components between the inner and outer bearing surfaces. These rolling elements mediate the contact between the gyro system and housing, transforming direct sliding friction into rolling friction, thereby reducing friction coefficients and eliminating the stick-slip effect while maintaining bearing support function

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The plain sliding bearing mechanism is replaced with a rolling element bearing mechanism. This substitution changes the fundamental mechanical interaction from sliding friction to rolling friction, significantly reducing friction coefficients and preventing the stick-slip phenomenon that causes course errors in gyrocompass systems

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If plain bearings are selected to reduce stick-slip effect, then the friction is reduced, but the device complexity and selection effort increase considerably

Engineering Contradiction:
Improvefriction reductionVSAvoidbearing selection and design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The friction parameter is fundamentally changed by transitioning from sliding friction to rolling friction through the introduction of rolling elements. This parameter change achieves low friction operation without complex bearing selections, as the rolling element mechanism inherently provides superior friction characteristics compared to plain bearings

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Spherical or cylindrical rolling elements are employed to replace flat plain bearing surfaces. The curved surfaces of the rolling elements enable rolling motion, fundamentally changing the friction characteristics and eliminating stick-slip effects without requiring complex bearing designs or extensive selection processes

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Reliability

If cardanic suspensions are used, then the bearing support is improved, but angular errors in pendulum deflections occur due to gimbal error

Engineering Contradiction:
Improvebearing support performanceVSAvoidpendulum deflection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The bearing is segmented into distinct functional components: an inner bearing component supporting the gyro system, an outer bearing component forming part of the housing, and rolling elements connecting them. This segmentation allows each component to be optimized for its specific function while eliminating the interconnected angular errors inherent in cardanic suspension systems

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Spherical rolling elements or surfaces are employed to create a self-aligning bearing mechanism. The spherical geometry allows the gyro system to pivot freely in multiple directions without the angular errors and gimbal mistakes that occur in cardanic suspensions, thereby improving measurement precision while maintaining bearing support

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 solution significantly enhances the performance and accuracy of the gyrocompass by reducing friction, preventing the stick-slip effect, and allowing for larger pendulum angles, resulting in improved return accuracy and course quality.

Implementation Method 1

A rolling element self-aligning bearing... with rolling elements running in the first intermediate space... the friction in the bearing is reduced

Methodology Applied
Scientific EffectRolling friction: Friction

Implementation Method 2

the roller bearing components are guided in a correspondingly safe manner so that they do not fall out and absorb the bearing forces at predetermined points

Methodology Applied
Scientific EffectMechanical contact and force distribution: Mechanical Force

Data Source

PatentEP2836731B1Sperical rolling element bearing, in particular for the gyro of a gyro compass and gyro compass with such a bearing
Publication Date: 2016.08.10 RAYTHEON ANSCHIITZ GMBH
  • EP2836731B1 patent drawingFigure 1
  • EP2836731B1 patent drawingFigure 2
  • EP2836731B1 patent drawingFigure 3

AI summary

A rolling body pendulum bearing is described, particularly for supporting gyroscopic systems of a gyrocompass, comprising: a rotational body (14, 18) with a convex outer surface section (14c) that is partially spherical relative to the first axis; a first hollow body (8) comprising a first hollow chamber (16) that holds the rotational body (14, 18) in the region of the partially spherical outer surface section (14c) thereof, the hollow chamber having a first opening (4) on a first end face (8a), a second opening (6) on a second end face (8b) lying opposite the first end face (8a) and a concave inner surface section (8c) that is partially spherical relative to a second axis (26) and lies between the two openings (4, 6), a first intermediate space (16) being formed between the partially spherical outer surface section (14c) of the rotational body (14) and the partially spherical inner surface section (8c) of the first hollow body (8); rolling bodies (10) running in the first intermediate space (16); and a first cage (12) in the first intermediate space (16), said cage holding the rolling bodies (10). The rolling body pendulum bearing additionally comprises: a first stop (20) provided on the rotational body (14, 18), which abuts the first cage (12) and/or at least one adjacent rolling body (10) when the rotational body (14, 18) is in a maximum pivoting position in relation to the second axis (26); and a second stop (2d) in the region adjacent to the first stop (20), with which the first cage (12) or at least an adjacent rolling body (10) simultaneously comes into contact in the maximum pivoting position of the rotational body (14, 18). The location and design of the rotational body (14, 18), the first hollow body (8), the rolling bodies (10) and the first cage (12) are such that the rolling bodies (10) still remain substantially inside the intermediate space (16) in the maximum pivoting position of the rotational body (14, 18).