Rotation Transmission Device Backlash Reduction

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Solution Overview

Problem

Helical gears are expensive and time-consuming to manufacture due to the need for complex metal molds, and they are not cost-effective for reducing backlash in rotation transmission devices.

Innovation Solution

A rotation transmission device using inexpensive spur gears with a linking part supported by an inclinable and rotatable supporting part, featuring an urging mechanism to press the gears together, reducing backlash and enhancing operability while minimizing manufacturing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If helical gears are used to reduce backlash, then the backlash between gears is reduced, but the manufacturing cost increases due to expensive metal molds and prolonged shot cycles

Engineering Contradiction:
Improvebacklash reductionVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive helical gears with inexpensive spur gears. Although spur gears traditionally have backlash, the invention compensates through the urging mechanism that presses the gears together, eliminating the need for costly helical gear manufacturing while achieving similar backlash reduction

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the operational parameters of spur gears by introducing an urging mechanism that applies continuous pressing force. This parameter change (from zero pressing force to continuous pressing force) transforms the performance of simple spur gears to match or exceed that of complex helical gears, achieving backlash reduction without increasing manufacturing cost

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If helical gears are used to reduce backlash, then the backlash between gears is reduced, but the manufacturing time increases due to complex mold operations

Engineering Contradiction:
Improvebacklash reductionVSAvoidmanufacturing speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent substitutes complex helical gears with simple spur gears that can be manufactured quickly using inexpensive molds. The urging mechanism compensates for the traditional disadvantages of spur gears, enabling fast production without sacrificing backlash performance

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of manufacture

If spur gears are used instead of helical gears, then manufacturing cost is reduced, but backlash increases

Engineering Contradiction:
Improvemanufacturing costVSAvoidbacklash
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces an urging mechanism as an intermediary element between the spur gears. This mechanism mediates the interaction between gears by applying continuous pressing force, thereby eliminating the backlash that would otherwise be present in simple spur gear systems while maintaining the cost advantages of using spur gears

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If multiple separate parts are used for the supporting structure, then the gears can be properly positioned and urged, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvegear engagement stabilityVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the supporting structure and urging mechanism into an integrated single component. This consolidation maintains the functional requirements of positioning and urging the gears while reducing the number of separate parts, thereby simplifying the device structure and reducing manufacturing cost without compromising gear engagement stability

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

The solution effectively reduces backlash and enhances operability using spur gears, achieving stable gear engagement and cost savings by simplifying the manufacturing process and reducing the number of parts.

Implementation Method 1

an urging part configured to urge the linking part so that the third gear is pressed to the first gear and the fourth gear is pressed to the second gear

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

The inner circumferential surface of the accommodating part of the present invention is spaced from the linking part. In this structure, since there is a space between the linking part and the inner circumferential surface of the accommodating part, no frictional force is generated between them

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3296590B1Rotation transmission device
Publication Date: 2020.06.03 ALPS ALPINE CO LTD
  • EP3296590B1 patent drawingFigure 1
  • EP3296590B1 patent drawingFigure 2
  • EP3296590B1 patent drawingFigure 3

AI summary

A rotation transmission part (40) is urged by urging parts (30e1, 30e2, 30e3) toward a rotation reference line (02) on a Z1 side with respect to engaging parts (63c) while the engaging parts (63c) of the rotation transmission part (40) are supported by the supporting parts (30b) of the supporting body (30). Therefore, the rotation transmission part (40) can be inclined. The third spur gear (61) and first spur gear (20a) engage each other under a certain pressing force, and the fourth spur gear (71) and second spur gear (83) engage each other under the certain pressing force, so backlash is suppressed during the transmission of rotation.