some aspects of traceability of camshafts and large gears · some aspects of traceability of...

O. Jusko et al CMM workshop CENAM 2010 ‹Nº›

Some aspects of traceability of camshafts

and large gears

Otto Jusko, Folke Santel, Frank Härtig, Waheed Adeyemi, Kerstin Rost, PTB Braunschweig, Germany

Raimund Volk / Hommel-Etamic GmbH, Schwenningen, Germany


topics

development and manufacturing of a camshaft standard

strategies for evaluating of cam profiles

estimation of measurement uncertainty

standardization

Contents – Part 1 camshaft meas.


cylinder coordinate shaft measuring instruments

1st meeting PTB / industry June 2005

profile shapes at steep surfaces

high-precison rotation axis

objectives

comparability of measurement results

traceability to national standards and SI system

acceptance tests

motivation


components

1 reference surface dealing as rotational datum

3 bearing surfaces L1, L2, and L3

2 excentric circular discs Ex1 und Ex2

2 cams N1, and N2

camshaft standard


measures

length = 300 mm

mass = 1,4 kg

hardness = 61 HRC

measurement parameters

Probing force = 2 N

camshaft standard


parameters

ϕN: cam rotational angle

hN: cam stroke

probing geometry

radius probe (disc)

flat probe (rod)

camshaft standard


function oriented evaluation

Starting with inlet …

… proceeding with outlet

alignment

coordinate system of drive

camshaft standard

cam zenith

cam rot. angle

ca

m s

tro

ke

H

dir. of rotation

h: cam stroke at ( rel. measure )

H: cam stroke (abs. measure)

main cam


application in machines / combustion engines

roller follower (circular)

flat follower

morphological filtering

moving point of contact

conversion

camshaft standard

roller follower

(rolling tap)

flat follower

(sliding tap)

cam profiles


measurement instruments

camshaft measuring instrument

form measuring instrument

hardness …

dimensional parameters

diameter

profile form

straightness / parallelism

roundness

…

camshaft standard - measurements


camshaft datums

manufacturing: live centers

engine: bearing surfaces

measurement

camshaft measuring instrument:

– live centers

form measuring instruments:

– centered

camshaft standard - measurements


form measuring instrument

centering to excenter

application of reversal procedure

parameters

roundness = 1,4 µm

straightness = 2,3 µm

… prototype values !

basic parameters


synthetic profiles

simple rule geometries

analytical computation possible

comparison procedure

evaluation as pseudo measurement

diff. pseudo measurement - theory

software validation

Reference result

Test data

Test software

Test result

Comparison test result vs. reference

PTB certificate


profile synthesis

circle segments and tangents

radius and angle offsets

sampling

“Probing“ of the synthetic profile

numerical profile as reference

Software test – test data


fitting procedure

angular position of cam

definitions required

Software test – reference software

Fitting angle

ref. curve

actual curve

Cam profile

speed profile

cam form deviation

area equality after alignment

Slope 100%

Slope 60 %

Slope 60 %Slope 100%

alignment areaalignment area

opening closing


Software test – result example

data

set

Reference Datadifferences

error free parameters

intended errorBase-

Radius

[mm]

Cam

stroke

[mm]

Angle to

datum

[mm]

Base

Radius

[mm]

Cam

stroke

[mm]

datum

angle

[mm]

Base

circ-

[mm]

Base

circ+

[mm]

HN-

[mm]

HN+

[mm]

N2.1R 20,0000 5,0000 0,0000 none 0,0001 0,0000 0,0000 0,0000 0,0000 -0,0001 0,0001

N2.2R 20,0000 5,0000 14,0000 angle deviation 14° 0,0001 0,0000 0,0000 0,0000 0,0000 -0,0001 0,0001

N3.1R 18,0000 7,0000 0,0000 shrinked by 0.7 mm 0,0001 -0,0004 0,0000 -0,0004 -0,0003 -0,0004 -0,0003

N3.2R 18,0000 7,0000 0,0000 Inflated by 0.4 mm 0,0001 0,0001 0,0000 0,0001 0,0001 0,0000 0,0001

N4.1R 16,0000 7,0000 0,0000alternating positive and negative

deviations of ±0.3 mm-0,0001 0,0001 0,0000 0,0001 0,0001 0,0001 0,0002

N5.1R 23,0000 5,0000 0,0000 cam stroke increased by 1,3 mm 0,0001 -0,0002 0,0000 -0,0001 -0,0001 -0,0001 -0,0001

N5.2R 23,0000 5,0000 0,0000 cam stroke decreased by 0,8 mm 0,0001 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000

N6.1R 15,0000 6,0000 0,0000 flank circles shrinked by 0.9 mm 0,0001 0,0000 0,0000 0,0000 0,0000 0,0000 0,0001


challenges

global production has to deliver the same results

various measurement instruments may be applied

missing definitions

coordination of users and manufacturers

agreement for mandatory evaluation methods

draft as (inter)national standard

comparison measurements with camshaft standards

standardization


Part II – Large gear standard

Background

Economic Importance of Large Gears

Assuring the Quality of Large Gears

Measuring Instruments

Importance of Measurement Uncertainty

Concepts of Traceability

Motivation

Establishing a reliable and economically efficient quality control

Realization

Large Gear Measurement Standard

First measurement results

Concepts of evaluating the measurement uncertainty in industry

Experimental uncertainty budget

VCMM-Gear: Monte-Carlo Simulation

Conclusion & Outlook


Economic Impact of Large Gears

2008:

Worldwide total wind energy capacity: 120 800 MW

Min. 36,000 Wind Turbine Generators (WTG) worldwide

(Germany alone: 20 000)

Approx. 75 % equipped with gearboxes

2012:

Worldwide total wind energy capacity: 300 000 MW

(DEWI scenario)

Growing market for new WTG and therefore gearboxes

Increasing demand for large gears

Gear diameters up to 3000 mm

Sourc

e: H

eadhuey,

Wik

imedia

Com

mons, Lic

ence: G

NU

fdl


Economic impact of large gears

Sourc

e: H

eadhuey,

Wik

imedia

Com

mons, Lic

ence: G

NU

fdl

Wind Turbine Generators

Designed life expectancy 20 years – Operating time 13 years

Highly reliable, low-maintenance gear box

Smooth, quiet running, low noise emission

High-quality gears, especially for offshore-turbines

Required tolerances:

Some 10 µm for major gear specifications

ISO 1328-1:1995

d = 1000 mm, b = 400 mm, mn = 20 mm, accuracy grade 5:

F = 21 µm, Fβ = 18 µm

Even stricter requirements for inspection processes


Quality assurance of large gears

Measuring Instruments

Coordinate Measuring Machines

Gear Measuring Instruments

Gears:

Standard measuring task

Modern instruments:

Gear maximum dimensions:

diameter: 3 800 mm

height: 2 000 mm

weight: 20 000 kg

Larger gears:

special applications

Challenges for large gears

Alignment, deformation

Reliable Measurements needed


Designing a large gear standard

Design parameters

Industrial requirements

Limited measuring facilities at PTB

Expanded measurement uncertainty less than U(k=2)=5 µm for involute profile

and helix slope deviations

Segmentation allows easy handling and shipping

Dismountable countermass for symmetric weight distribution


Quality assurance of large gears

Parameter Value

Number of teeth z 38

Normal module mn 20 mm

Pressure angle n 20°

Face width b 400 mm

Helix angle β / hand 0°/spur; 10°/R; 20°/L

Outside diameter da 1000 mm

Weight 450 kg (700 kg)

Reference bands diameter

(form deviation)

200 mm (1 µm)


Large gear standard during meas.


Commercial gear standard


First measurements

Flankenlinie 0° Rechtsflanke

Helix 0° right flank

-10

-8

-6

-4

-2

0

2

4

6

8

10

-400 -350 -300 -250 -200 -150 -100 -50 0

Zahnbreite in mm

Facewidth in mm

Fla

nken

lin

ien

ab

weic

hu

ng

in

µm

Heli

x d

evia

tio

n i

n µ

mGood profile and helix form

Reproducibility of measurements

Profile slope deviation fH <= 1.1 µm

Helix slope deviation fHb <= 2.2 µm


Muchas gracias !

some aspects of traceability of camshafts and large gears · some aspects of traceability of...

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