Wheel Bearing Outer Member Hot and Cold Forging Process

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Solution Overview

Problem

The existing wheel bearing apparatus manufacturing process is inefficient due to a high number of processing steps and increased manufacturing costs, primarily because of the need for lathe turning to form bolt seating surfaces, which complicates the production and increases cycle time.

Innovation Solution

The wheel bearing apparatus employs hot forging for the outer member and cold forging for the bolt insertion bores and seating surfaces, eliminating the need for lathe turning and reducing the number of processing steps, while ensuring accurate finishing and improved mounting accuracy through cold forging of bolt insertion bores and chamfered portions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If lathe turning is used to form bolt seating surfaces, then mounting accuracy is improved, but the number of processing steps increases and manufacturing cost increases

Engineering Contradiction:

Improvemounting accuracyVSAvoidnumber of processing steps

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent changes the manufacturing method from lathe turning to cold forging, altering the process parameters to achieve both high precision and efficiency. Cold forging with specifically designed dies produces the bolt seating surfaces with required accuracy while eliminating multiple machining steps

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The bolt seating surfaces are formed during the cold forging process before final assembly, integrating the formation of mounting surfaces into the primary manufacturing step rather than requiring subsequent machining operations

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If lathe turning is used to form bolt seating surfaces, then mounting accuracy is improved, but manufacturing cost increases

Engineering Contradiction:

Improvemounting accuracyVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent transitions from subtractive machining (lathe turning) to formative manufacturing (cold forging), changing the fundamental production parameter to reduce material waste and processing time while maintaining or improving surface accuracy

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The formation of bolt insertion bores, chamfered portions, and bolt seating surfaces is merged into a single cold forging operation, consolidating multiple functions into one manufacturing step that reduces overall cost

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If cold forging is used for bolt insertion bores and seating surfaces, then the number of processing steps is reduced, but manufacturing precision must be maintained

Engineering Contradiction:

Improvenumber of processing stepsVSAvoiddimensional and positional accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent optimizes cold forging parameters including die design, forging pressure, and temperature control to achieve dimensional and positional accuracy comparable to or exceeding traditional machining methods

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical cutting system of lathe turning with a plastic deformation system in cold forging, using precisely engineered dies to form features with high accuracy through controlled material flow rather than material removal

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 enhances blank yield and reduces manufacturing costs by simplifying the production process, improving dimensional and positional accuracy of bolt insertion bores, and maintaining the strength and rigidity of the wheel bearing apparatus.

Implementation Method 1

The outer member is previously formed by hot forging

Methodology Applied

Scientific EffectHot forging: Deformation

Implementation Method 2

A seating surface for the fastening bolts is formed by cold forging on an outboard-side surface of the body mounting flange

Methodology Applied

Scientific EffectCold forging: Deformation

Data Source

PatentUS9573419B2Wheel bearing apparatus and its manufacturing method

Publication Date: 2017.02.21 NTN CORP

AI summary

A wheel bearing apparatus has an outer member, an inner member and double row rolling elements freely rollably contained between double row inner raceway surfaces and outer raceway surfaces of the inner member and the outer member. A plurality of bolt insertion bores, that fastening bolts pass through to fasten to the knuckle, are formed on the body mounting flange at plurality of positions circumferentially along the body mounting flange. The outer member is previously formed by hot forging. A seating surface for the fastening bolts is formed on an outboard-side surface of the body mounting flange by cold forging.