Low-Profile Rack and Pinion Gear Drive System

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Solution Overview

Problem

Conventional rack and pinion gear systems require additional structures to counteract separation forces, leading to increased size and complexity.

Innovation Solution

A low-profile gear drive system where the pinion responds to the movement of the rack, utilizing a stabilizer bearing to redirect separation forces back to the pinion, eliminating the need for external bearing arrangements, and incorporating a ball screw and motor for linear motion conversion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional structures are used to counteract separation forces in conventional rack and pinion systems, then the gears remain engaged, but the system size increases

Engineering Contradiction:
Improvegear engagement stabilityVSAvoidsystem sectional area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent combines the bearing support function directly into the rack structure by creating bearing surfaces on the rack itself, eliminating the need for separate external bearing arrangements. This merging of functions maintains gear engagement stability while reducing system size and sectional area.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rack is designed to provide its own bearing support through integrated bearing surfaces that react to separation forces. The rack serves itself by incorporating the support function within its own structure, eliminating the need for additional external support structures.

Inventive Principle:
Principle #25Self-service

2Reliability

If external bearing arrangements are used to counter separation forces, then gear disengagement is prevented, but device complexity increases

Engineering Contradiction:
Improveprevention of gear disengagementVSAvoidbearing arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bearing support function is merged into the rack structure through integrated bearing surfaces, eliminating the need for separate external bearing arrangements and their associated complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the bearing support function from external components and relocates it directly to the rack structure, simplifying the overall system by removing unnecessary intermediate components.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If conventional rack and pinion systems are designed with external support structures, then separation forces are countered, but manufacturing cost increases

Engineering Contradiction:
Improveseparation force counteractionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By merging the bearing support function into the rack structure through integrated bearing surfaces, the patent reduces the number of separate components that need to be manufactured and assembled, thereby reducing manufacturing cost while maintaining separation force counteraction capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rack provides its own bearing support through self-contained bearing surfaces, eliminating the need for additional external support structures and reducing overall manufacturing complexity and cost.

Inventive Principle:
Principle #25Self-service

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 maintains a small aspect ratio without external bearings, reducing the sectional area and enabling a low-cost, low-profile packaging suitable for applications like missile fin control, while preventing disengagement of the rack and pinion gears.

Implementation Method 1

incorporating a ball screw and motor for linear motion conversion

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP1999004B1Gear drive system and method
Publication Date: 2010.11.24 RAYTHEON CO
  • EP1999004B1 patent drawingFigure 1
  • EP1999004B1 patent drawingFigure 2
  • EP1999004B1 patent drawingFigure 3

AI summary

The disclosed system, device and method for providing a low aspect rack and pinion assembly includes a rack engaged with a ball screw and a pinion. The rack is generally responsive to the rotation of the ball screw and the pinion is generally responsive to the movement of the rack. The separating forces generated by the engagement of the rack and pinion are suitably reacted by one or more stabilizer bearings engaged with the structure of the rack and pinion to prevent the rack and pinion from disengaging while maintaining a low aspect profile.