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1 Abstract Number: 008-0619 Abstract Title: Advanced Development Design CAE Model Utilizing New JIT: Application to Automotive Intelligence CAE Methods Author: Kakuro Amasaka Organization: School of Science and Engineering, Aoyama Gakuin University Address: 5-10-1 Fuchinobe, Sagamihara-shi, Kanagawa-ken, 229-8558 Japan E-mail: [email protected] Phone/Fax: Tel:+81.42.759.6313, Fax: +81.42.759.6556 Type: POMS 19th Annual Conference of the Production and Operations Management Society, La Jolla, California, U.S.A. May 9 to May 12, 2008

Abstract Number: 008-0619 Abstract Title: Advanced

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Page 1: Abstract Number: 008-0619 Abstract Title: Advanced

1

Abstract Number: 008-0619

Abstract Title: Advanced Development Design CAE Model Utilizing New JIT:

Application to Automotive Intelligence CAE Methods

Author: Kakuro Amasaka

Organization: School of Science and Engineering, Aoyama Gakuin University

Address: 5-10-1 Fuchinobe, Sagamihara-shi, Kanagawa-ken, 229-8558 Japan

E-mail: [email protected]

Phone/Fax: Tel:+81.42.759.6313, Fax: +81.42.759.6556

Type: POMS 19th Annual Conference of the Production and Operations Management Society,

La Jolla, California, U.S.A. May 9 to May 12, 2008

Page 2: Abstract Number: 008-0619 Abstract Title: Advanced

2

An Advanced Development Design CAE Model Utilizing New JIT:

Application to Automotive Intelligence CAE Methods

Kakuro Amasaka

Aoyama Gakuin University

5-10-1 Fuchinobe, Sagamihara-shi, Kanagawa-ken, 229-8558 Japan

Tel: +81.42.759.6313, Fax: +81.42.759.6556, E-mail: [email protected]

Abstract: With a view to assisting corporations to survive in the “worldwide quality

competition”, the author has proposed the “Advanced Development Design CAE Model”

utilizing New JIT. In an effort to verify its validity, the author has created the “Automotive

Intelligence CAE Methods”. Furthermore, as an extended application of these methods, the

author has also established the “Automotive Intelligence CAE Management System Approach

Methods”. The author has analyzed an issue of worldwide concern, the oil seal leakage

mechanism on an automobile transaxle, and has created the “Intelligence CAE Software - Oil

Leakage Simulator” that incorporates CG Navigation in order to ensure high quality

assurance.

Keywords: New JIT, Advanced Development Design CAE Model, Automotive Intelligence

CAE Methods, CG Navigation, Intelligence CAE Software - Oil Leakage Simulator, Toyota

and NOK

1. Introduction

At present, advanced companies in both Japan and overseas in the automobile industry and

others are endeavoring to survive in today’s competitive market by expanding their global

production while also aiming to respond to the “worldwide quality competition”. [1] Given

this management situation, the author has recognized the necessity of making advancements

Page 3: Abstract Number: 008-0619 Abstract Title: Advanced

3

in the product development system. A new area of interest has arisen in the study of a design

management model that realizes high quality assurance in automobile development designing.

This new area is the shift of business process management from experimental evaluation

based on actual vehicles and tests, to predictive evaluation based on highly reliable CAE

(Computer Aided Engineering) analysis. Given this background, the author [2] proposes an

“Advanced Development Design CAE Model, ADDCM”, which strategically deploys New

JIT (New Just in Time). The validity of this model has been verified by the author and it will

help realize the simultaneous achievement of QCD (Quality, Cost, and Delivery). Furthermore,

by deploying ADDCM the author has created and verified the effectiveness of the “Total

Quality Assurance (QA) High Cycle-ization Business Process Method” and the “Stratified

Intelligence CAE Management System Approach Method”.

These methods are both a part of the “Automotive Intelligence CAE Methods” that the

author has also created in an effort to reform the automobile development design process.

Stated in more concrete terms, the author has invented the “Automotive Intelligence CAE

Management System Approach Methods” and with the cooperation of the Toyota and NOK

corporations has used these methods to investigate the transaxle oil seal leak mechanism that

has been a bottleneck technological problem for the world’s automobile manufacturers. [2, 3]

At the implementation stage, the author developed a “visualization device” that could

capture the dynamic behavior of the oil leak. This knowledge was then combined with the

“CG Navigation” function that employs computer graphics technology to create the

“Intelligence CAE Software - Oil Leakage Simulator” and this made highly reliable CAE

analysis possible. As a result of this outcome, precise improvement of designs and process

management could be implemented. This then led to an even more dramatic effect, the

achievement of “transaxle high quality assurance” in the marketplace.

Page 4: Abstract Number: 008-0619 Abstract Title: Advanced

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2. Expectations for Automotive Development Production and Simulation Technology

For manufacturers to be successful in the future global market, they need to develop

products that make strong impressions on consumers and then supply such products in a

timely fashion through effective corporate management. The mission of the automotive

manufacturers in this environment of rapidly changing management technology, is to be

prepared for the “worldwide quality competition”, so that they are not pushed out of the

market and to establish a new management technology model that enables them to offer

highly reliable products of the latest design that are also capable of enhancing the value to the

customer. [2, 4]

In the field of management technology for the automobile development and production

processes that are being considered here, excessive repetition of “prototyping, testing, and

evaluation” is being carried out to prevent the “scale-up effect” in the bridging stage between

testing and mass production. This has resulted in an increase in the development period and

cost. Therefore, it is now necessary to reform the conventional development and production

method. [2] More specifically, it is increasingly vital to realize the “simultaneous achievement

of QCD” (Quality, Cost and Delivery) that satisfies the requirements of developing and

producing high quality products, while also reducing the cost and development period through

incorporation of the latest simulation technology “CAE” (Computer Aided Engineering) and

statistical science called SQC (Statistical Quality Control). [5, 6]

In the vehicle development process employed in the past, after completing the designing

process, problem detection and improvement were repeated mainly through the process of

prototyping, testing, and evaluation. In some current automotive development, a prototype of

a vehicle body is not manufactured in the early stage of development due to the utilization of

CAE and SE (Simultaneous Engineering) activities, and therefore the development period has

been substantially shortened (first from four years to two years, and then to one year at

Page 5: Abstract Number: 008-0619 Abstract Title: Advanced

5

present). [2] Given this background, it is clear that the conventional development process of

repeated evaluation using prototypes is no longer capable of handling this task. Collaboration

between CAE and SE activities, which are now faster and more precise, will be indispensable

for fully utilizing the accumulated knowledge database. As discussed so far, expectations are

high for the realization of super short-term development, which would be done through

utilization of CAE. In other words, there will be a conversion from the so-called

“development through real object confirmation and improvement” to “prediction evaluation

oriented development”. [3, 6, 7]

3. Proposal of the Advanced Development Design CAE Model Utilizing New JIT

The author will apply “New JIT”, a new principle of next generation management

technology, in order to create and propose the “Advanced Development Design CAE Model”

in an effort to reform the business process of development design.

3.1 Concept of “New JIT” for Innovating Management Technology

The “new deployment of global marketing” for prevailing in today’s “global quality

competition” is the most important issue for the manufacturing industry. Particularly for

Japanese manufacturers, in order to survive in the global market, the urgent management issue

is “global quality and simultaneous launching (optimal production), in other words, the

simultaneous achievement of QCD, which is a prerequisite for succeeding in global

production. [1, 2]

In order to create attractive products that are also superior in QCD, it will be vital for each

of the business/sales, development/designing, and production divisions to carry out

management in such a way as to link the entire organization of their own divisions. Therefore,

what is needed is a strategic, next generation management technology that can become a

unifying force for optimizing (strongly linking) the business process cycles of all divisions, in

Page 6: Abstract Number: 008-0619 Abstract Title: Advanced

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other words, creating a new organizational and systematic behavior principle. Given this

background, the author [8] hereby proposes a new management technology principle, New JIT,

as indicated in Figure. 1.

New JIT is the Just in Time (JIT) system [9, 10] not only for manufacturing, but also for

customer relations, sales and marketing, product planning, R&D, design, production

engineering, logistics, procurement, administration, and management. It will enhance the

innovation of the business process and the introduction of new concepts and procedures. New

JIT contains hardware and software systems for accelerating the optimization (high linkage)

of work process cycles of all the divisions and aims to strengthen management technology so

that it reaches the level of management strategy as shown in Figure 2.

The hardware system of this strategic management technology system (New JIT) is made

up of three core principles: TDS (Total Development System), TPS (Total Production

System), and TMS (Total Marketing System). The aim of New JIT is to organically link these

three core principles of TDS, TPS, and TMS in order to unify the entire business process from

development design technology to control technology and finally to sales, and thereby reform

management technology.

These three core systems are each a core technology required for establishing the new

Total M arketingSystem

Total Developm ent System

Service

InspectionProduction

engineering

Evaluation byexam ination

developm ent

Engineering design

design

Product planningProduct

managementMarket research

Manufacturing

TQM by utilizingScience SQC

TMS TMS TDS TDS

TPS TPS

Preparation for production

How to sell?

Was production satisfactory ?

How to produce ?

W hat is to be produced ? Sales

What is needed ?

How was the result ?

TotalProductionSystem

Science SQC

TQM -SResearch and

Profile

What is the expected state ?

Figure 1 New JIT, a New Management Technology Principle

Page 7: Abstract Number: 008-0619 Abstract Title: Advanced

7

management technology in each of the divisions: business/sales, development designing,

production engineering/production, and general affairs/management. For the software system

of this strategic management technology system, the author [11, 12] proposes a new principle

of quality management, Science TQM (TQM promotion incorporating Science SQC) which is

called TQM-S. This has been done in order to improve the business process quality of all

divisions depicted in the figure.

More specifically, this is an operation strategy for next generation quality management that

was developed to promote a more scientific approach, and its validity has been demonstrated

in recent years. The aim is to rationally systemize and organically organize the application of

new quality management through parallel use of Information Technology (IT) and Science

SQC. At present, New JIT, which will allow management technology to evolve into a

management strategy, has proved effective in a number of cases at Toyota and other

companies and will now be introduced to a number of countries.

TDS

(b) Product value improvement

(c

) Bui

ldin

g tie

s w

ith c

usto

mer

(a)

Mar

ket c

reat

ing

activ

ities

Customer focus

Product value

Quality, cost and delivery

Customer information

Development and

production

Sales and marketing

Marketing system TMS

Customer-oriented quality assurance

(d) Customer value improvement

Shop appearance Brand Reliability

Service Merchandise Product planning and

design

Customer

delight

Customer satisfaction

Customer retention

TMS

TPS

High linkage cycle for the business process

improving

G enerator M entor

P rom oter

E ng ineering

Process m anagem ent

Philosophy

Inspec tion

M arket

Production

P Productiontechnolog y

Sys tem

Elem ent

cost and delivery

(b) P roduction by m anagem ent

(d) P roductio n by partners hip

P lan

D es ign

Prod uctio n

philoso ph y

TP S Inform ation technolog y

(a) P

rodu

ctio

n by

info

rmat

ion

H um an m anagem ent

Q uality,

(c) P

rodu

ctio

n by

tech

nolo

gy

Fig. 3 Three core systems of New JIT, the Evolution of the Management Technology

S oftw are science

H ardware science

D es ign proc ess

B ehavioral Science

D es ign R ev iew

D es ign p hilos ophy

C ustom er-in

Past d ataon use

environm ent

P reced ingand next

p rocess es

D es ign technolog y

System eng ineering

Phenom en on analysis by using

C AE and S QCTD S Shared use of

inform aion Optim ized des ign Technolo gy

c reation

(b ) M anag em ent-based d esig n

(d ) D esigner's d ec is io n-b ased d es ign

Plann ing

(a) I

nfor

mat

ion-

base

d de

sign

(c) T

echn

olog

y-ba

sed

desi

gn

E lem ental technology

D es ig n beh av ior

New JIT with

three core principles

TDS

(b) Product value improvement

(c

) Bui

ldin

g tie

s w

ith c

usto

mer

(a)

Mar

ket c

reat

ing

activ

ities

Customer focus

Product value

Quality, cost and delivery

Customer information

Development and

production

Sales and marketing

Marketing system TMS

Customer-oriented quality assurance

(d) Customer value improvement

Shop appearance Brand Reliability

Service Merchandise Product planning and

design

Customer

delight

Customer satisfaction

Customer retention

TMS

TPS

High linkage cycle for the business process

improving

G enerator M entor

P rom oter

E ng in eerin g

Process m anagem ent

Philosophy

Inspec tion

M arket

Production

P Productiontechnolog y

Sys tem

Elem ent

cost and delivery

(b) P roduction by m anagem ent

(d) P roductio n by partners hip

P lan

D es ign

Prod uctio n

philoso ph y

TP S Inform ation technolog y

(a) P

rodu

ctio

n by

info

rmat

ion

H um an m anagem ent

Q uality,

(c) P

rodu

ctio

n by

tech

nolo

gy

Fig. 3 Three core systems of New JIT, the Evolution of the Management Technology

S oftw are science

H ardware science

D es ign proc ess

B ehavioral Science

D es ign R ev iew

D es ign p hilos ophy

C ustom er-in

Past d ataon use

environm ent

P reced ingand next

p rocess es

D es ign technolog y

System eng ineering

Phenom en on analysis by using

C AE and S QCTD S Shared use of

inform aion Optim ized des ign Technolo gy

c reation

(b ) M anag em ent-based d esig n

(d ) D esigner's d ec is io n-b ased d es ign

Plann ing

(a) I

nfor

mat

ion-

base

d de

sign

(c) T

echn

olog

y-ba

sed

desi

gn

E lem ental technology

D es ig n beh av ior

New JIT with

three core principles

Figure 2 New JIT Strategy, High-linkage Cycle for Improving Business Processes

Page 8: Abstract Number: 008-0619 Abstract Title: Advanced

8

3.2 The Importance of “Highly Reliable CAE Analysis” Utilizing New JIT

Next, the author will attempt to grasp the need for and importance of “highly reliable CAE

analysis” that utilizes New JIT. This will be done from the standpoint of “high quality

assurance manufacturing – the simultaneous achievement of QCD”. In order to do this the

author investigated the utilization status, problems, and validity of CAE throughout the entire

work flow (from development/design, to production and sales) at automotive companies

(body manufacturers and parts suppliers).

This is summarized in Figure 3. In the case studies (1 to 3) conducted by the author [2, 5, 6]

up to now, the progress of the CAE analysis technology has been illustrated, but it has become

clear that its systematic and organizational application is still inadequate. The first CAE

application problem is (i) that the mechanism of technical problems that are expected to be

clarified through CAE analysis is not well understood and implemented in the CAE model.

The second application problem (ii), is that the CAE analytic method has not been shown to

be capable of reliable prediction and control to the point that CAE can replace the prototyping

and testing evaluation process. The desired gap (analysis error) between the real machine

(actual vehicle) evaluation data and the CAE data should be in the order of only a few

percent.

Figure 3 Issues When Applying CAE to Development Design Reform

C A E application tasks for sim ultaneous achievem ent of Q C D

Q uality C ost D elivery term

Control

Poorrecognition of field w orkers

Lack of evaluation

Capable of exam ining m ultip le rem edy plans

U nable to achieve Q C D sim ultaneously

A nalysis technique Evaluation technique

H ow to avoid lack of evaluation and errors?

H ow to perform D R w ithout object? H ow to keep

consistency betw een the actual m achine and C A E ? M ethodology?

-R evolution from “actual item confirm ation and im provem ent type” to “forecast and evaluation type”-

A pplication technology

Capable of relativeevaluation from pastdata

Expansion of prelim inary

exam ination &application rangeY oung & dispatched

w orkers increase. C annot control

quality & am ount.Increase of CA E tasks

Expansion of CA E

equipm ent &labor cost

V erification experim ents are necessary.

U nable to reduce prototype

m anufacturing costs etc.

The developm ent period does not becom e shorter.

A bsolute evaluation

is im possib le.

Errors are not taken into

consideration for evaluation.

Poor repeatability of forecast result

A m ount of m anual w ork does not

decrease.

The CA E m odel is not based on full

understanding of the m echanism .

The CA E m ethod including possib ility of errors is not established

or generalized.

C A E application tasks for sim ultaneous achievem ent of Q C D

Q uality C ost D elivery term

Control

Poorrecognition of field w orkers

Lack of evaluation

Capable of exam ining m ultip le rem edy plans

U nable to achieve Q C D sim ultaneously

A nalysis technique Evaluation technique

H ow to avoid lack of evaluation and errors?

H ow to perform D R w ithout object? H ow to keep

consistency betw een the actual m achine and C A E ? M ethodology?

-R evolution from “actual item confirm ation and im provem ent type” to “forecast and evaluation type”-

A pplication technology

Capable of relativeevaluation from pastdata

Expansion of prelim inary

exam ination &application rangeY oung & dispatched

w orkers increase. C annot control

quality & am ount.Increase of CA E tasks

Expansion of CA E

equipm ent &labor cost

V erification experim ents are necessary.

U nable to reduce prototype

m anufacturing costs etc.

The developm ent period does not becom e shorter.

A bsolute evaluation

is im possib le.

Errors are not taken into

consideration for evaluation.

Poor repeatability of forecast result

A m ount of m anual w ork does not

decrease.

The CA E m odel is not based on full

understanding of the m echanism .

The CA E m ethod including possib ility of errors is not established

or generalized.

Page 9: Abstract Number: 008-0619 Abstract Title: Advanced

9

At present however, the “development of CAE software performing within the error

limitations and establishment of its usage” are not satisfactory. As a result, it has been

surmised that despite its expanded usage, CAE is not yet sufficient for the simultaneous

achievement of QCD or for reducing the length of the development period. The main focus of

CAE utilization by development and designing engineers is first, structural modeling and

estimation for prediction. Second is control, and third is factor (cause) analysis. Particularly in

the case of highly reliable CAE analysis for “prediction evaluation based development”, when

a highly precise absolute value evaluation is expected to be able to match the actual vehicle

and testing evaluation results, then the modeling for prediction and control must inquire into

the strict cause and effect relationship. In this case a physical-chemical, universal structural

model is required, and advanced unique technology (such as elucidation of the “mechanism”

that is causing the problems to occur) holds the key to successful development.

3.3 Proposal of the Advanced Development Design CAE Model “ADDCM”

At present, in the business process from automobile development design through to

production and sales, the “high cycle-ization of development design” in particular, is

becoming a pending problem. [2, 13] In general, to achieve the “scale-up effect” during the

bridging stage between the actual vehicle (prototypes and testing) and mass production, a

process of successive prototyping, testing, and evaluation must be carried out repeatedly. This

results in higher costs and longer development periods. Therefore, in order to break out of this

pattern it is now vital to reform the conventional development design method.

In an effort to deploy a global production strategy that employs New JIT, it is urgent to

leave behind the conventional development design process of low intelligent productivity in

which prototyping and testing are repeated on a trial and error basis. This is especially the

case for design activities that ultimately aim to result in product commercialization. Instead, it

Page 10: Abstract Number: 008-0619 Abstract Title: Advanced

10

is necessary to concentrate accumulated design knowledge through a strategic collaboration

between the related departments in order to conduct “highly reliable CAE design” that makes

full use of the latest simulation technology “CAE analysis” capabilities. [7, 14]

Therefore, in order to break away from the old-fashioned product development method, in

an aim to establish a high-cycle, next generation development design process, the author [2]

proposes the “Advanced Development Design CAE Model, ADDCM”, as shown in Figure 4.

The mission of ADDCM is the simultaneous achievement of QCD. This is the basis for

high quality assurance manufacturing and is also essential for the realization of CS (Customer

Satisfaction), ES (Employee Satisfaction), and SS (Social Satisfaction). In order to create this

model, digitized design (A) will be used in an effort to reform the development design system

(B) and promote the shift to a super-short-term development process system (C). Furthermore,

it will be necessary to realize the “sharing of intelligent technology” among the development

designers (D).

The necessary parts to make this model into a reality are shown in the figure above. The

objective of this model is to (I) scientifically interpret (convert into explicit knowledge) the

The Key to the Strategic Development of “New JIT”

(1)Customer ScienceCustomer Orientation

Science-ization

Advanced Development

Design CAE Model

Global Production -Same Quality Worldwide, and Production

at Optimum Locations-

High Quality Assurance

Simultaneous Achievement of QCD

(E) Innovation of Employee Images

(D) High Accuracy of the Prediction &

Control

(B) Development Design System Reform

(C) Super-short-term Process System Reform

(A) Digitized Design

(2) Highly Reliable

Development Design System

(3) Intelligent Simulation

(4) Intellectual Technology

Integrated System

Global Development Strategy - Same Quality Worldwide, and Development at

Optimum Locations -

- High-cycle Next-generation Development Business Process -

Figure 4 Advanced Development Design CAE Model “ADDCM”

Page 11: Abstract Number: 008-0619 Abstract Title: Advanced

11

customer’s wants (implicit knowledge) that are drawn out by “Customer Science” [15]

through incorporation of “Science SQC”. The second objective is to innovate and upgrade the

model to (II) a highly reliable development design system that reflects the results obtained in

the first step. What makes this possible is (III) “intelligent simulation” by means of creating

“highly reliable CAE analysis software” that is capable of shortening the development period

through accurate prediction and control. To implement this, it will be vital to (IV) introduce

an “intelligent technically integrated network system” called “TTIS” (Total SQC Technical

Intelligence System) [11, 16] where the accumulated know-how and latest technical

information of all departments are commonly shared, and then to systematically and

organizationally operate this system.

In the next chapter “Automotive Intelligence CAE Methods” will be proposed that will

become the concrete deployment method for the proposed “ADDCM”.

4. Application of the “Automotive Intelligence CAE Methods” Utilizing ADDCM

In an effort to deploy “ADDCM” and reform the process of automobile development

design, the author proposes the “Total Quality Assurance (QA) High Cycle-ization Business

Process Method” and the “Stratified Intelligence CAE Management System Approach

Method” as a part of the “Automotive Intelligence CAE Methods” mentioned above.

4.1 Total QA High Cycle-ization Business Process Method

As the first step, the author proposes the development design business process approach

method. This is done from the standpoint of Verification/Validation (divergence of CAE from

theory and divergence of CAE from testing) in order to make highly reliable CAE analysis

possible that is consistent with the market – testing – theory profile. The author [2, 11]

therefore recommends the introduction and utilization of the “Total Quality Assurance High

Cycle-ization Business Process Method” which systematically and strategically realizes high

quality assurance by incorporating the analysis made via the core technologies of Science

Page 12: Abstract Number: 008-0619 Abstract Title: Advanced

12

SQC and Management SQC as shown in Figure 5.

For example, in order to solve the pending issue of a technology problem in the market, it is

necessary to create a universal solution (general solution) by clarifying the existing six gaps

(1 to 6 in the figure below) in the process consisting of Theory (technological design

model)–Experiment (prototype to production) – Calculation (simulation) – Actual Result

(market) as shown on the lower left of Figure 5 below. To accomplish this, the clarification of

the six gaps (1 to 6) in the business processes across the divisions, shown on the lower right

of Figure 5 below, is of primary importance. By taking these steps, the intelligent technical

information owned by the related divisions inside and outside the corporation will be totally

linked, thus reforming the business process of development design. In this way the rational

deployment of “Customer Science”, which is a key to the realization of the “highly reliable

development design system”, will also be achieved.

4.2 Stratified Intelligence CAE Management System Approach Method

Next, as the second step, the author [2] proposes the “Stratified Intelligence CAE

Management System Approach Method” shown in Figure 6. This method contributes to “high

1.Exhortation to "Science SQC" 2.Exhortation to "Management SQC" Importance of managers’ roles (Decision making: money materials and manpower)

・Improving the engineering capability ↓

・Scientifically elucidating the gaps between principles and basic rules

←・Improving the job quality

↓ ・Grasping the true cause of poor communication between departments

Organizational problem Engineering problem

↓↓

Why are gaps (① to ⑥) generated ? ↓

It is necessary to improve the gaps by clarifying the reasons. ↓

Providing customers with intended products ↓

↓ Hypothesis Exploration

Explanation Verification Chase

Team Activities

④ ②

① ③

↓ Manufacturing← ↑

↓ →Designing ↑

↓→Marketing←

→ Planning← ↑ ⑥

④②

① ③

↓ Experiment←

↓ →Calculation

↑ ↓ →Actual result←

① → Theory← ↑ ⑥

⑤ ⑤

Figure 5 Total QA High Cycle-ization Business Process Approach Methods

Page 13: Abstract Number: 008-0619 Abstract Title: Advanced

13

quality assurance and the simultaneous achievement of QCD”.

Among many of the automotive manufacturers there is a gap between the actual vehicle

testing results and the CAE analysis results in the development design stage, as shown in

Figure 6. Due to a lack of confidence in the CAE evaluation results, they tend to heavily rely

on survey tests (Step I). Even among advanced manufacturers, the utilization of CAE stops at

relative evaluation (Step II). The author recognized the dilemma that the utilization ratio of

CAE compared to actual vehicle (prototype) and testing evaluation is about 25% for survey

purposes and about 50% for relative evaluation. In other words, the effectiveness of CAE for

the purpose of reducing the length of the development period has not been proven. This also

revealed that the usual solution for technical problems, that are difficult to solve theoretically,

is actual vehicle (prototype) and testing evaluation based on empirical or CAE evaluation

conducted by trial and error using a makeshift modeling process.

To help improve this situation, the author [11, 16] clarified the mechanism causing the

problem by means of the research results accumulated in the “intelligent technological

integration system”, in other words, the combination of visualization technology and Science

SQC. Then, drawing on that knowledge, further studies focused on improving the precision of

Level of statistical analysis

I Survey

II Relative eval.

III Absolute eval.

Fig. 6 Total Intelligence CAE Management Model 7)

IV Robust design

Simultaneous QCD achievement

CAE100%

CAEActual vehicle

CAE

Generalized model

Mechanism clarification

Science SQC-aided SQC Technical Methods

N7/RE

SQC/RE

MA/RE

DOE/REHigh precision

prediction and control

Super reduction in development design period and simultaneous achievement of QCD: Use of intelligent modeling for prediction and control

Actual Vehicle

*CAE:Gap

Current status

XCAEActual

Vehicle

Actual Vehicle

Development without prototyping: (III) Absolute evaluation:Modeling and inquiry into mechanisms are necessary.

Level of statistical analysis

I Survey

II Relative eval.

III Absolute eval.

Fig. 6 Total Intelligence CAE Management Model 7)

IV Robust design

Simultaneous QCD achievement

CAE100%

CAEActual vehicle

CAE

Generalized model

Mechanism clarification

Science SQC-aided SQC Technical Methods

N7/RE

SQC/RE

MA/RE

DOE/REHigh precision

prediction and control

Super reduction in development design period and simultaneous achievement of QCD: Use of intelligent modeling for prediction and control

Actual Vehicle

*CAE:Gap

Current status

XCAEActual

Vehicle

Actual Vehicle

Development without prototyping: (III) Absolute evaluation:Modeling and inquiry into mechanisms are necessary.

I Survey

II Relative eval.

III Absolute eval.

I Survey

II Relative eval.

III Absolute eval.

Fig. 6 Total Intelligence CAE Management Model 7)

IV Robust design

Simultaneous QCD achievement

CAE100%CAE100%

CAEActual vehicle

CAE

Generalized model

Mechanism clarification

Science SQC-aided SQC Technical Methods

N7/RE

SQC/RE

MA/RE

DOE/REHigh precision

prediction and control

Super reduction in development design period and simultaneous achievement of QCD: Use of intelligent modeling for prediction and control

Actual Vehicle

*CAE:Gap

Current status

XCAEActual

Vehicle

Actual Vehicle

Development without prototyping: (III) Absolute evaluation:Modeling and inquiry into mechanisms are necessary.

Figure 6 Stratified Intelligence CAE Management System Approach Method

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14

the CAE analysis. As a good example of CAE utilization, attention was focused on the

effectiveness of “SQC Technical Methods such as, N7 (New Seven Tools), RE (Reliability),

SQC (Statistical Quality Control), MA (Multivariate Analysis), and DE (Design of

Experiments)” [21]. These are capable of taking a functional approach to variable factor

analysis of the real machine (actual vehicle) testing data and then feeding it back to the CAE

analysis software through a deductive methodology in order to derive general solutions.

Next, in Step III the mechanism causing the pending technological problem was clarified

by using “visualization technology”. Then, by creating a “general model”, the “absolute

evaluation” (III) was made possible, an “intelligent simulation” could be realized, and the

prediction and control of the mechanism could be made highly precise through the use of

CAE analysis [15]. Based on this knowledge, in Step IV a “robust design” method was

employed to eliminate the reliance on actual vehicle and testing results. This method allowed

for a “parameter study” to be made in which the influential factors and their effects, which are

important to achieving “optimal design”, were reflected. Furthermore, this also led to

prevention of the “scale-up effect” at the mass production stage and the realization of a rise in

the CAE utilization rate. In the next chapter the validity of the “Automotive Intelligence CAE

Methods Utilizing ADDCM” will be verified.

5. Application Example: Analysis of Oil Seal Leakage and Development of Highly

Reliable CAE Software

In this chapter the “Toyota and NOK cooperative task team activity - Reliability improvement

of the transaxle oil seal” case study will be presented. This case study applied the

“Automotive Intelligence CAE Methods” and the validity of the “Advanced Development

Design CAE Model” proposed by the author was also verified.

5.1Oil Seal Function

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15

An oil seal on an automobile’s transaxle prevents the oil lubricant within the drive system

from leaking from the drive shaft. It is comprised of a rubber lip molded onto a round metal

casing. The rubber lip grips the surface of the shaft around its entire circumference, thus

creating a physical oil barrier. In this case the sealing ability of microscopic roughness on the

rubber surface is of primary importance. [17] The parameters for the sealing condition of the

oil film involve not only the design of the seal itself, but also external factors such as shaft

surface conditions, shaft eccentricity, and so on. Contamination of the oil by minute particles

was found to be of particular importance to this problem since these are technical issues

which involve not only the seal, but also the entire drive train of the vehicle. [18]

5.2 Automotive Intelligence CAE Management System Approach Methods

In general, experienced development design staff and CAE engineers understand the

mechanism that is causing the “oil seal leak” as implicit knowledge. The formulation of this

“implicit knowledge and know how that is dependent on individual expertise” is an essential

step to refining CAE analysis as a problem-solving method. It is also a “problem solving

approach that utilizes empirical rules and knowledge”. The creation of “highly reliable CAE

software” will allow this valuable “implicit knowledge” to be turned into “explicit

knowledge” and is why creating this siftware is so important. [2, 7, 9]

Therefore, the author [2] applied the previously mentioned “Automotive Intelligence CAE

Methods” and developed highly reliable CAE software in an effort to help solve the

“automobile transaxle oil seal leakage problem” that had become a global technological issue.

As an intelligent application method of this software, the author proposed the “Automotive

Intelligence CAE Management System Approach Methods”, as shown in Figure 7. In the case

of the “oil seal leakage”, this was a pending problem where no progress was being made in

the reduction of claims from the marketplace or the functional fault. At the time, no one knew

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16

where exactly the fault was occurring or what mechanism was causing it. It was important to

search out the “root cause” in order to solve this technological problem. [20, 21]

To accomplish this, first, it was important to “visualize the dynamic behavior of the

problem” by using actual vehicles and carrying out testing (A). At this point the expertise of

specialists from both inside and outside the company was brought together through

“partnering” activities. The most advanced SQC methods were used to analyze and

investigate the complex cause and effect relationships. It was vital to “deduce the fault

mechanism”. Next, in order to carry out (B) a precise fault analysis and factor analysis, N7,

SQC, RE, MA, and DE were combined and utilized to “search out and identify previously

unknown or overlooked latent causes”. In this way a logical thinking process was used to

carry out a logical investigation into the “cause of the fault mechanism”.

Furthermore, all of this knowledge and information was then unified through (C) the

creation of “CAE Navigation Software” (CAE-CG-NS) that employs computer graphics (CG)

to reproduce the “visualization” of the actual vehicle and testing data so that it can be made

*Partnering *N7 * SQC * RE*Mechanism inference

(A)

Visualization

(Hypothesis)

Actual vehicle &experiment

Clarification of mechanism of drive unit oil seal leak: Toyota and suppliers

Mode

ling

Investigation of latent factors

Failure analysis (RE) * MA * DE

Modeling: CAE *MA * DE * QA network * RE- Input parameters, governing equation, identify principle factors, prediction and control, technical model and output, output display method, results eval. method

(C) Navigation CG

(Qualitative model)

Actual vehicle*CAE

(D) Numeric value

Simulation (Quantitative

model)

CAE CAE

(E)-Evaluation.-Design -Implement

Design

Test

CAESoftware design

SQC

(A) (B) (C) (D) (E)

◎ ◎ ◎ ○ ◎◎ ◎ 〇 ○ 〇○ 〇 〇 ◎ ◎

△ ○ 〇 ◎ △〇 ◎ △ 〇 ◎

(B) Mechanism

(Techniques)

*Partnering *N7 * SQC * RE*Mechanism inference

(A)

Visualization

(Hypothesis)

Actual vehicle &experiment

Clarification of mechanism of drive unit oil seal leak: Toyota and suppliers

Mode

ling

Investigation of latent factors

Failure analysis (RE) * MA * DE

Modeling: CAE *MA * DE * QA network * RE- Input parameters, governing equation, identify principle factors, prediction and control, technical model and output, output display method, results eval. method

(C) Navigation CG

(Qualitative model)

Actual vehicle*CAE

(D) Numeric value

Simulation (Quantitative

model)

CAE CAE

(E)-Evaluation.-Design -Implement

Design

Test

CAESoftware design

SQC

(A) (B) (C) (D) (E)

◎ ◎ ◎ ○ ◎◎ ◎ 〇 ○ 〇○ 〇 〇 ◎ ◎

△ ○ 〇 ◎ △〇 ◎ △ 〇 ◎

(B) Mechanism

(Techniques)

(B) Mechanism

(Techniques)

Figure 7 Automotive Intelligence CAE Management System Approach Methods

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17

consistent on a qualitative level. At this stage, where “CAE-CG-NS” is being created, it was

important to carry out actual vehicle and testing work so that a model (qualitative model)

could be made for the cause and effect relationships of the unknown mechanism. It would

then become extremely important to use this model to reduce the divergence (gap) between

the results from the actual vehicle testing and the CAE “absolute value evaluation”.

In addition, at the stage of developing the highly reliable CAE software (D), exhaustive

actual vehicle testing was carried out in order to convert the leak mechanism from “implicit

knowledge” into precise “explicit knowledge”. The information gained from these work

processes would then be unified and a “highly credible numerical simulation (quantitative

model)” would be carried out to make absolute value prediction and control possible. In the

final stage (E), the CAE analysis results are then verified by comparing them to the actual

vehicle testing results. In the case of a decentralized organization and business process (such

as shown in Figure 7) it is essential that the specialists in the fields of design, testing, CAE

analysis, CAE software development, and SQC, carry out cooperative team activities,

“partnering” (◎Main, Sub, △Support) at each stage of the work process (A to E).

The author [24, 28] acted as the coordinator to promote integration of the Toyota and NOK

cooperative team and as a result dramatic improvement in the number of claims from the

market were achieved as illustrated in the following chapter.

5.3 Understanding of the Mechanism through Visualization

According to NOK, the oil leaks occurred due to wear. The result of a wear test on the oil

seals indicated that a running distance of 400,000 km (equivalent to 10 years or more of

vehicle life) is regarded as sufficiently reliable for the oil seal design. [22] However,

according to Toyota’s fault repair records for parts that had market claims, which makes use

of DAS (Dynamic Assurance System) [23], there were sporadic cases of the oil leak problem

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18

occurring in vehicles that had not even reached half of the running distance set by NOK. [18]

Judging from the survey and analysis of parts returned from customers due to claims, the

cause of the failure was identified as being due to the accumulation of foreign matter between

the oil seal lip and the contact point with the transaxle shaft, resulting in insufficient sealing.

Oil leaks were found not only during running, but also in new vehicles at rest. Thus, it was

determined that the cause is poor foreign matter control during the manufacturing process,

and that it is vital to improve the production quality in this process.

The established theory used to be that fine metal particles (on the order of microns in size)

would not adversely affect the lip sealing effect. [24] However, when these particles combine

to produce relatively larger particles, do they then affect the sealing effect? Also, what about

the effect of alignment between the drive shaft and the oil seal (fixing eccentricity) during

assembly? In addition, if oil leakage occurs due to foreign matter accumulation on the oil seal

lip during transaxle assembly, what is the minimum particle size that causes the problem? The

answers to these questions were all unknown since the dynamic behavior of the oil leakage

had not yet been visualized. This meant that the true cause also had yet to be clarified.

Consequently, a device was developed to visualize the dynamic behavior of the oil seal lip,

as shown in Figure 8, in order to turn this "unknown mechanism" into explicit knowledge. [4,

22] As shown in the figure, the oil seal was immersed in the lubrication oil in the same

manner as the transaxle, and the drive shaft was changed to a glass shaft that rotated

Fig.12 Outline of Oil Seal Visualization Equipment

Optic fiber

Glass shaft

Oil seal

Camera

Attacheddrawing

Spindlemotor

Figure 8 Oil Seal Visualization Equipment

C o n t a c t w i d t h o fs e a l l ip p o t i o n ; L a r g e

C o n t a c t w i d t h o f s e a l l ip p o t io n ; S m a l l

G r o w i n g o f t h e f o r e ig n m a t t e r s a t t h e c o n t a c t s e c t i o n

V e r y f in e f o r e i g n m a t t e r s

V is u a l iz a t io n d e v i c e

Figure 9 Oil Leakage Mechanism (Test-1)

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19

Foreign matter on sliding surface

of recovered part (SEM)

20 μ m

Foreign matter on Sliding surface after reproduction test (Video, 10 rpm)

200 μ m

eccentrically via a spindle motor so as to reproduce the operation that would occur in an

actual vehicle. The sealing effect of the oil seal lip was then visualized using an optical fiber.

It was conjectured that in an eccentric seal with one-sided wear, the foreign matter becomes

entangled at the place where the contact width changes from small to large. Three trial tests

were carried out to ascertain if this was true or not. Based on the examination of faulty parts

returned from the market and the results of the visualization experiment, it was observed that

very fine foreign matter (which was previously thought to not impact the oil leakage problem)

grew at the contact section, as shown in Figure 9 (Test-1).

It was also confirmed from the results of the component analysis that the fine foreign

matter was a powder produced during gear engagement inside the transaxle gear box. This

fine foreign matter on top of microscopic irregularities on the lip sliding surface resulted in

microscopic pressure distribution which eventually led to the degrading of the sealing

performance (Figure 10, Test-2). Also, the presence of this mechanism was confirmed from a

separate observation that foreign matter had cut into the lip sliding surface, thereby causing

aeration (cavitations) to be generated in the oil flow on the lip sliding surface. This caused

deterioration of the sealing performance, as shown in Figure 11 (Test-3). The figure indicates

that cavitations occur in the vicinity of the foreign matter as the speed of the spindle increases,

even when the amount of foreign matter that has accumulated on the oil seal lip is relatively

small.

1.7 mm

DDiirreeccttiioonn ooff ccaavviittaattiioonnss

Figure 11 Oil Leakage Mechanism (TESt-3)

FFoorreeiiggnn mmaatttteerrOOiill bbaatthh

ssiiddee

AAttmmoo-- SSpphheerriicc

ssiiddee

0 rpm

300 rpm 1100 rpm

MMeenniissccuuss lliinnee

Figure 10 Oil Leakage Mechanism (TESt-2)

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20

As the size of the foreign matter gets bigger, the oil sealing balance position of the oil seal

lip moves more toward the atmospheric side and causes oil leaks at low speeds or even when

the vehicle is at rest. This fact was unknown prior to this study, and therefore was not

incorporated into the original design of the oil seals. [19, 22]

5.4 Fault and Factor Analyses

Before studying the mechanism of the oil seal leaks described in Section 5.3, both NOK

and Toyota believed that the wear on leaking oil seal lips would follow a typical pattern. The

empirical knowledge based on the results of individual oil seal reliability tests was that the

unit axle is highly reliable, and would ensure 400,000 km or more in B10 life (the period of

time in which less than 10% of the items fail). It was thought that the oil seal lip should wear

gradually because of smooth contact between the oil seal lip and the rotating drive shaft, and

also because of an oil film in between the two rough surfaces. [18]

As a result of the study and investigation discussed however, it was found that metal

particles generated from the gears in the differential case accelerated the eccentric wear of the

oil seal lip, making the expected design life unobtainable. Since the wear pattern was not

simple, it had to be confirmed that the oil leak problem could be reproduced with the faulty

oil seals returned due to customer claims. At this point the author [2, 3] performed a search on

the research that Toyota had performed up to now using “TTIS”. The “SQC technical

method” was also applied and the information obtained up to now was further classified and

summarized using the N7 (affinity diagrams and association charts among others) to promote

the “fault analysis” and the “factor analysis”.

First, in addition to defective oil seals, non-defective ones were collected on a regular basis

to check if the oil leak could be reproduced and for comparison through visual observations.

Next, transaxle units from vehicles, both with and without oil leak problems,

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21

were also collected on a regular basis to check if the leak could be reproduced in the same

way. Integrating the results from transaxles both with and without defective oil seals

confirmed that the defect could be reproduced and in all of these tests, the oil leaks were

reproduced as expected. Based on these test results, a Weibull analysis was then conducted as

described below.

The plot of the results (based on defective items that resulted in claims) is shown in Figure

12. It clearly shows a bathtub-shaped failure rate for the oil seal failures. The three shape

parameter (m) values correspond to the three different failure modes. This analysis resulted in

the following new knowledge:

(1) In the initial period, the failure rate is decreasing (slope (m) < 1), in the middle period it is

constant (slope = 1), and in the latter period it is increasing (slope > 1) indicating a

bathtub-shaped failure rate. The failure rate in each of the three sections can be modeled by a

different Weibull distribution, so that the failures can be modeled by a sectional Weibull

model.

(2) The initial failures (where the failure rate is decreasing) occur up to a running distance of

50,000km. Failures in the intermediate range (where the failure rate is constant) occur up to

120,000km. Finally, failures occurring above this value (where the failure rate is increasing)

Inf

luen

tial r

atio

of e

ach

fact

or %

0

2 0

4 0

6 0

8 0

T h e p er io d o f u s in g

M ile a g e H a rd ne ss o f ru b b e r

T h e lip a v era g e w ea r w id th

D es ig n fa cto r o f h a rd n es so f o il s ea l rub b er is h ig h ly in f lu en tia l

1 0 0

F a c to r

T h e lip m arg ino f t ig h te n in g

Figure 12 Influential Effect of Each Factor

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22

are due to wear.

(3) The B10 mode life is approximately 220,000 km, about half the value stated as the design

requirement.

To confirm the reliability of these results, subsequent claims were analyzed using the

Toyota DAS system. Within the warranty period (number of years covered by warranty), the

total number of claims classified by each month of production (total number of claims from

the month of sale to the current month for vehicles manufactured in the same month) divided

by the number of vehicles manufactured in the respective month of production is about twice

the design requirement.

This agrees with the result of the above reliability analysis. The influence of five

dominating wear-causing factors (period of use, mileage, margin of tightening, hardness of

rubber, and average width of lip wear) was studied by two-group linear discriminate analysis

using both leaking and non-leaking parts collected in the past. The result showed high positive

discriminate ratios of 92.0% and 91.7% for both group 1 (leaking parts) and group 2

(non-leaking parts). [4] From the partial regression coefficients of the explanatory variables

in the linear discriminate function obtained, the most significant influence was found to be the

hardness of the rubber of the oil seal lip. The influence ratios for the five factors were

obtained by means of an orthogonal experimental design (L27), with three level values, which

were thought technically reasonable in consideration of the non-linear effects assigned to each

of them. [25]

Figure 13 shows the influence ratios of each factor contributing to the discrimination. The

figure shows that the hardness factor of the rubber is highly influential. This analytical result

was also convincing in terms of inherent technologies. To test the validity of this result, the lip

rubber hardness and the degree of wear on the other collected oil seals was examined further.

As a result, it has been confirmed that eccentric wear is more likely to shorten the seal life

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23

because the rubber hardness at the lip portion decreases. This result is consistent with the

established theory and empirical knowledge (empirical rules) obtained up to now. This survey

and analysis could not have been carried out successfully by the conventional and separate

investigation activities of Toyota or NOK. [22]

5.5 CG Navigation and Intelligence CAE Software - Oil Leakage Simulator

The author combined the “CG Navigation” function that explains the dynamic behavior of

the oil leak with the technological knowledge examined and acquired above, to create the

“Intelligence CAE Software - Oil Leakage Simulator”. [2]

Figure 14 shows a typical example of the modeling of the sliding surface condition that has

been created for the purpose of reducing the weight of the sliding surface of the oil seal

10

1

0.1

0.01 Small Large

C

umul

ativ

e fa

ilure

ratio

Mileage

F(t)[

%] m < 1

(Decreasing failure rate)

m =1.0(Constant failure rate)

m >1 (Increasing failure rate)

(Conventional conception) m=1.0 B10(Bearing 10%)life >400,000km Life was thought long enough

Concentrated “cause unknown”

Discovery of shorter life than conventionally conceived

(a)

(b)

(c)

Figure 13 Result of Weibull Analysis

Modeling of the sliding surface condition and oil behavior in the model seal (by authors’ editing)

A B

A B Air side

Oil side

Figure 14 CG Navigation and Intelligence CAE Software - Oil Leakage Simulator

Slid

ing

wid

th

Page 24: Abstract Number: 008-0619 Abstract Title: Advanced

24

contact part. Judging from what has been observed up to this point, it is necessary to have the

sliding surface minutely irregular and the parts that are actually in contact biased toward the

oil side. This is done in order to maintain a good sealing condition that will prevent oil leaks

from occurring at the contact part of the oil seals.

As shown in Figure 14, the upper section of the sliding surface is the oil side and the lower

section is the air side. The darkest black part indicates the areas that are actually in contact.

Among the conditions of characteristic values necessary for sealing, the minute roughness of

the sliding surface or the small black area representing the actual contact area can be

described in this way. Next, another condition is that this black area is biased toward the oil

side, which can be incorporated in the sliding surface model like this. Here, the two black

areas are not completely parallel, but rather the upper ends are found to be pointing inward.

This takes into account the condition of a real oil seal. The actual sliding surface of the oil

seal consists of countless tiny projections, which are represented by the black area, pointing in

random directions. However, statistically speaking, the directional orientation of these

projections shows counterbalancing characteristics.

In this model such factors have been taken into consideration. In other words, the two

model projections representing the random projections are arranged to face each other at the

same angle, so that a directionless model is presented. The author [2, 24] actually

photographed an oil seal reproducing this model sliding surface and observed the behavior of

the oil. The upper section in the figure is the oil side and the lower section is the air side,

while the rotating axis of the drive shaft (called “the shaft” hereinafter) rotates in the direction

of the arrows ( ). As the shaft rotates, a flow of oil in the same direction as the rotation is

generated and it flows along the two tiny projections.

With this situation in mind, let’s consider the cross sections of the tiny projections, A-A and

B-B. First of all, let’s look at the cross section A-A. At the oil inlet, the angle between the

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shaft and the microscopic projection is small. Because of this, a strong, hydrodynamic wedge

effect is produced, causing the oil film to become thicker and increasing the amount of flow to

the oil side. On the other hand, at the cross section B-B, the angle at the oil inlet is larger.

Consequently, the wedge effect is small and the oil film does not get thick, resulting in a

smaller amount of flow to the air side. Comparing the inlet flow and outlet flow here, the flow

rate into the oil side is larger and achieves sealing. This leak prevention phenomenon has been

reproduced and confirmed by an actual oil seal having the same characteristic values as the

above model, and therefore the validity of this sliding surface model has been verified.

It is this phenomenon that creates a circulation of the oil flowing in and out of the sliding

surface against the direction of the shaft rotation (V) when sealed, as shown in the figure. This

circulation, which is promoted by the tiny projections, is the very factor that separates the lip

sliding surface and the shaft and maintains a favorable fluid lubrication condition. This is in

line with the phenomenon explained at the beginning, and explains why the wear on the oil

seals is limited. The series of discussions to this point has sufficiently explained why the

newly designed oil seal suffers little wear and maintains it’s sealing effect for a long period of

time. The author has confirmed the leak proof phenomenon utilizing actual model seals. The

validity of the Sliding Surface Model – Sealing Mechanism Analysis was verified against the

results of actual vehicles and tests with a difference rate of 2%.

This clarified concept of Numerical Simulation by CAE – the Sliding Surface Model has

been applied to the development design engineering of high precision oil seals. That is to say,

as a result of incorporating the Intelligence CAE Software, the minute roughness on the

sliding surface has been controlled by regulating the composition of the materials. The next

factor concerning the biased distribution of roughness toward the oil side can be interpreted as

the bias of contact pressure distribution toward the oil side. Therefore, this factor has been

controlled by shape designing technology used for designing the seal lip.

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The result obtained from incorporating “CG Navigation” and “Intelligence CAE Software

for OL (Oil Leak) Analysis” has helped to identify and refine the high precision sealing

mechanism of oil seals. Furthermore, the study conducted by the author has established this as

a predictive engineering method for functional designing of oil seal parts.

6. Design Changes and Process Control for Improving Reliability

From the comprehensive knowledge gained in the previous chapter, “An Analysis of Oil

Seal Leakage and Development of the Highly Reliable CAE Software”, the following facts

were learned: (1) The result of the Weibull analysis and visualization tests showed that some

gears in the transaxle units had low surface hardness, and that there was a lot of wear during

meshing (causing the generation of minute metal particles) leading to an unusually short

operational life. It was recognized that it was necessary to prolong the life of these gears. (2)

The study confirmed that there was considerable variation in the oil seal lip rubber hardness

and this also had to be controlled.

Consequently, the author [2, 3] carried out the following improvements in order to ensure

high quality assurance for the transaxle.

(1) At Toyota, (i) improvement in wear resistance was achieved by increasing the gear surface

hardness through changes to the gear material and heat treatment. Furthermore, (ii) for

transaxles, improvements in the roundness and surface smoothness of the drive shaft

(resulting in the reduction of metal particles caused by the wear of gears in the differential

case) were achieved.

(2) At NOK (iii) the mean value of the oil seal lip rubber hardness was increased and the

specification allowance range narrowed. This, in combination with improvements in oil seal

lip production technology (including in the rubber compound mixing process to suppress

deviation between production lots), led to improved process capability. In addition, (iv) the

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27

higher coaxial centers of metal oil seal housings, the alignment of coil springs and seal lips,

the contact width of the oil seal lips, and the thread profile identified during the design

modifications were properly monitored and controlled during the production process to ensure

the high quality of the oil seals.

(3) Furthermore, in order to control the generation of foreign matter, the new information that

the oil starts leaking when fine metal particles of approximately 75 um in size are present

(caused by the yarn dust from gloves during work, rubbish, powder dust, etc.) was publicized.

Based on this new knowledge about when the oil leaks start, both Toyota and NOK promoted

work improvements at their production sites and reduced the cases of early faults in the

market.

Due to these comprehensive reliability improvements the B10 life was increased to greater

than 400,000 km. As a result, the cumulative number of market claims per production month

was reduced to less than 1/20th the previous level and the desired effect was achieved as

shown in Figure 15.

6. Conclusion

With a view to helping corporations survive the “worldwide quality competition”, the

author brought about reform of the development design business process. This reform entailed

Fig. 15 Effectiveness of Market Claim Rate Reduction

Trend in market claim rate 12 months after saleHigh

Production year/month

Cla

im ra

te (%

)

Low

Average no. of claims

98/0

3

00/0

7

98/1

2

Measure 9Measure 9

Measure 2Measure 2

Measure 8Measure 8

Measure 6Measure 6Measure 7Measure 7

Measure 5Measure 5Measure 4Measure 4

Measure 1Measure 1Measure 3Measure 3

96/0

4

Kaizen to improve design quality

1/2 Claims1/4 Claims

1/8 Claims

Kaizen to improve production quality

Measure 10Measure 10Measure 11Measure 11

Measure 12Measure 12

Measures to stabilize production process control

Fig. 15 Effectiveness of Market Claim Rate Reduction

Trend in market claim rate 12 months after saleHigh

Production year/month

Cla

im ra

te (%

)

Low

Average no. of claims

98/0

3

00/0

7

98/1

2

Measure 9Measure 9

Measure 2Measure 2

Measure 8Measure 8

Measure 6Measure 6Measure 7Measure 7

Measure 5Measure 5Measure 4Measure 4

Measure 1Measure 1Measure 3Measure 3

96/0

4

Kaizen to improve design quality

1/2 Claims1/4 Claims

1/8 Claims

Kaizen to improve production quality

Measure 10Measure 10Measure 11Measure 11

Measure 12Measure 12

Measures to stabilize production process control

Figure 15 Effectiveness of Market Claim Rate Reduction

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the change from conventional development methods that use experimental evaluation based

on actual vehicles and tests, to predictive evaluation based on development methods that use

highly reliable CAE analysis. Given this background, the author has proposed the “Advanced

Development Design CAE Model” utilizing New JIT, and has been able to present a new

automobile development design method, “Automotive Intelligence CAE Methods” that utilize

the “Total Quality Assurance High Cycle-ization Business Process Method” and the

“Stratified Intelligence CAE Management System Approach Method.

Furthermore, as an extended application of these methods, the author has also established

“Automotive Intelligence CAE Management System Approach Methods”. In order to

demonstrate their effectiveness, these methods were applied to the clarification of the

mechanism of the transaxle oil seal leakage problem, which was a bottleneck problem for

vehicle manufacturers worldwide. In order to realize highly reliable CAE analysis, first, the

author devised the “Intelligence CAE Software - Oil Leakage Simulator” that incorporated

CG Navigation for the purpose of preventing oil seal leakage. This has contributed to a

remarkable reduction in market claims regarding this problem, and a substantial result has

been achieved in the field of ensuring high quality assurance.

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