Sintered Gear Tooth Chamfering With a Wheel Brush

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Solution Overview

Problem

Conventional methods for chamfering the edges of sintered gear teeth are inefficient, leading to long machining cycle times and shape errors, making them unsuitable for mass production due to the mechanical weakness of green compacts and the risk of chipping during high-speed machining.

Innovation Solution

A method using a wheel-type brush with radially protruding bristle members to chamfer the edges of sintered gear teeth by rotating and moving the brush in a circumferential direction, allowing for increased machining speed without chipping the green compact, and maintaining the flatness of the end surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional cutting methods are used to chamfer green compact teeth, then machining speed can be increased, but the green compact edges chip due to mechanical weakness

Engineering Contradiction:

Improvemachining speedVSAvoidedge integrity

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The patent replaces conventional mechanical cutting tools with a brush-type tool that uses abrasive bristles to chamfer the green compact teeth. This substitution allows for higher machining speeds without chipping the edges, as the brush gently abrades the surface rather than forcibly cutting it. The brush tool includes a holder with multiple bristles arranged in a specific pattern, enabling effective chamfering while maintaining edge integrity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If conventional chamfering methods are used, then edge removal can be achieved, but machining cycle time increases due to inefficiency

Engineering Contradiction:

Improvemachining efficiencyVSAvoidmachining cycle time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The brush tool is segmented into multiple bristles arranged in specific rows and columns, with each bristle contributing to the chamfering action. This segmentation allows simultaneous contact with multiple points on the tooth edge, enabling parallel material removal and significantly reducing machining cycle time compared to conventional single-point cutting tools.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The brush-type chamfering method enables continuous material removal along the entire tooth edge as the brush rotates or moves across the green compact surface. Unlike intermittent cutting methods, the brush maintains continuous contact and removes material uniformly, maximizing machining efficiency and reducing cycle time.

Inventive Principle:

Principle #20Continuity of useful action

3Productivity

If high-speed machining is applied to green compacts, then productivity improves, but shape errors increase due to mechanical weakness

Engineering Contradiction:

Improvemachining speedVSAvoidshape accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces forceful mechanical cutting with gentle abrasive action from brush bristles. This substitution enables high-speed machining without inducing shape errors, as the brush bristles flex and conform to the green compact surface, removing material uniformly without causing deformation or vibration-related inaccuracies.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 approach significantly reduces machining cycle time, prevents edge chipping, and maintains the flatness of the end surfaces, enhancing the productivity and quality of sintered gears by allowing for faster and more precise chamfering.

Implementation Method 1

chamfering an edge of the teeth by a brush, the edge being constituted by the end surfaces and the outer peripheral surface

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 2

sintering the green compact that has been chamfered

Methodology Applied

Scientific EffectSintering: Sintering

Data Source

PatentUS11802617B2Method of manufacturing sintered gear

Publication Date: 2023.10.31 SUMITOMO ELECTRIC INDUSTRIES LTD

AI summary

A method of manufacturing a sintered gear includes preparing a green compact having two gear-shaped end surfaces, one on each of two sides in an axial direction of the green compact, and having a plurality of teeth on an outer peripheral surface formed between the two end surfaces; chamfering an edge of the teeth by a brush; and sintering the green compact. The brush is a wheel-type brush including a disk-shaped wheel and a bristle member radially protruding from an outer periphery of the wheel. The chamfering includes disposing the brush with respect to the green compact such that the axial direction of the green compact and an axial direction of the wheel intersect with each other; bringing a tip of the bristle member into contact with a tooth bottom edge; and relatively moving the brush in a circumferential direction of the green compact while rotating the brush.