innovation is our nature - saint-gobain · innovation is our nature maintenance free bearings •...

Innovation isour nature

Maintenance free bearings

• Minimum coefficientof friction

• Low wear and size-ability

• Eliminates noise

• Vibration damping

• Heavy metal free

NORGLIDE®-advantages

at a glanceö Minimum coefficient of friction for solid materials

ö Maintenance free and self-lubricating

ö Minimum stick-slip effect

ö High pU (PV) for absolute dry-running and stability

ö Takes up edge loading and compensates for misalignment

ö Eliminates noise

ö Vibration damping

ö No water absorption

ö Good formability

ö Excellent wear resistance

ö Temperature resistant

2 • Saint-Gobain Performance Plastics

Table of contents

NORGLIDE® range of bearings 4 – 5

NORGLIDE®-Types 6 – 11

Compounds 12

Coefficient of friction 13

Life expectancy of NORGLIDE® bearings 14 – 19

Design of the bearing 20

Tolerancing 21

Sizing 22

Torques 23

Installation of NORGLIDE® bearings 24 – 25

Measuring NORGLIDE® bearings 26 – 27

Corrosion resistance 28 – 29

Quality 30 – 31

Practical Application 32 – 35

Saint-Gobain Performance Plastics worldwide 36

3

Fluoropolymers have been used as bearing materials for over 50 years. Since its dis-covery in 1938, Poly Tetra Fluoro Ethylene has continuously been developed andimproved. The addition of appropriate fillers gives the material specific propertieswhich alter its strength and coefficient of friction and enable it to perform a largevariety of tasks. Tape bearings modified this way (a blank of PTFE tape formedunder temperature) are the origin of our bearing program.

By encapsulating a metal fabric into PTFE, an important step forward was made:NORGLIDE® MP is a plastic material which allows the large-scale production of bear-ings. For the first time our customers are able to produce a specific torque or clear-ance by sizing the bearing. This is also possible with NORGLIDE® S which uses stretch-ed metal instead of the metal fabric.

The combination with a steel shell makes it possible to increase the load bearingcapability significantly. NORGLIDE® T combines steel and tape to provide noise andvibration damping properties and light-weight construction. Similarly when bond-ed to steel NORGLIDE® MP turns into NORGLIDE® M, NORGLIDE® S into NORGLIDE®SM. Both materials maintain their sizing capability to a large extent with the capa-bility of higher loads. They take up edge loading and compensate for misalign-ment. NORGLIDE® materials with a steel thickness ≥ 0.5 mm are suitable for produc-ing a press-fit in the housing.

The latest innovation is NORGLIDE® PRO the PTFE bearing with best load-carry-ing capabilities known today. With its complex composition - steel plate, structuredbronze layer with encapsulated PTFE sliding layer – its load-bearing capability isalmost twice as much as that of NORGLIDE® T, M and SM.

NORGLIDE® MP NORGLIDE® S

We develop customized solutionsthat will help our clients succeed.We offer a full line of high-perfor-mance bearing materials for themost diversified requirements.Selecting the proper material forthe individual application is thecore of our cooperation with thecustomer.You as the designer can count onus when it comes to providingcustom service.


The range of NORGLIDE® bearings

NORGLIDE® M NORGLIDE® SM

NORGLIDE® T NORGLIDE® PRO NORGLIDE® SMTL

“

5

„We specialize in

low coefficients

of friction,

low wear and

size-ability.

NORGLIDE® MP and SMaintenance free, flexible bearing tapesNORGLIDE® MP and NORGLIDE® S are maintenance free bearing materials made ofa metal support structure and a wear-resistant PTFE compound which offer highload capabilities. This combination of materials enables easy manual or automaticprocessing and installation. NORGLIDE® MP and NORGLIDE® S can be adapted tomany applications, including severe chemical environments.

The materials allow excellent sizing so that an interference fit of the bearing to theshaft can be designed to produce particular torques or eliminate play.

AvailabilityThe support structure is available in either tin bronze, stainless steel or aluminum. Thestandard PTFE compound contains glass fibers and graphite. Special PTFE compoundsare available on request. Fabricated parts include die-cuts, rolled cylinders, flanged cy-linders and deep-drawn bearings. NORGLIDE® MP and NORGLIDE® S can be preparedfor bonding (etched one side). They can be supported or backed with steel or plastics.

NORGLIDE® MP and S

NORGLIDE® MMaintenance free bearings with steel backingNORGLIDE® M is a composite material of NORGLIDE® MP bearing tape and steelbacking. This combination of material improves load capabilities while maintainingthe characteristics of NORGLIDE® MP, especially its sizing capability.

The bearings can be designed to be clearance free. Bearings of 1 mm of wall thick-ness or greater can be produced with an interference fit in the housing. Variousmethods are available to protect the steel shell from corrosion.

AvailabilityThe standard PTFE compound contains glass fibers and graphite. Special PTFE com-pounds are available on request. Fabricated parts include rolled bearings with orwithout an axial flange, deep-drawn bearings and die-cuts. The steel shell andmesh can be offered in stainless steel for chemically harsh environments.

NORGLIDE® M

Standard thickness table NORGLIDE® MPNom. Material Structurethick-ness

(mm) CuSn 6 Fabric 1.4401 Fabric

0.48 ö ö

0.78 ö ö

0.98 ö


Standard thickness table NORGLIDE® MNom. Material Structurethick-ness (mm) CuSn 6 Fabric Stainless steel fabric

Steel backing Stainless steel backing0.75 ö

1.0 ö

1.5 ö

1.57 ö

PTFE compound

Metal fabric

Material properties Norglide® MP SG Test Procedure Units Value

Maximum permissible specific bearing load at RT SG PL 0044 N/mm2 100 to 140

Coefficient of friction at RT on steel with ≥ 58 HRCat 4.8 N/mm2 and 0.058 m/s SG PL 0003 0.09 to 0.19at 70 N/mm2 and 0.0065 m/s SG PL 0003 0.06 to 0.10

Deformation under load(230C, at 100 N/mm2, 1 h) SG PL 0015 µm 30 ≤ x ≤ 90

Maximum continuous operating temperature °C 260

K factor at RT on steel with ≥ 58 HRC SG PL 0003 10-6mm3/Nm 0.12 to 0.18

The above mentioned performance values were measured in laboratory tests.They must not be considered as a specification for design.

Material properties Norglide® MSG Test Procedure Units Value



Deformation under load(230C, at 100 N/mm2, 1 h) SG PL 0015 µm ≤ 30




7

PTFE compound

Metal fabric

Steel backing

NORGLIDE® SMMaintenance free bearings with steel backingNORGLIDE® SM is a composite material of compounded PTFE, bronze stretchedmetal and steel backing. This material structure combines the bearing characteristicsof a PTFE compound tape with the sizing capabilities of stretched metal. These bea-rings can also be designed to be clearance free. Bearings of 1 mm wall thickness orbigger can be produced with an interference fit in the housing. Various methods areavailable to protect the steel shell from corrosion.

AvailabilityThe standard PTFE compound contains carbon and graphite. Special PTFE com-pounds are available on request. Fabricated parts include rolled bearings with orwithout an axial flange, deep-drawn bearings and die-cuts.

NORGLIDE® SM

NORGLIDE® SMTLMaintenance free bearings with steel backingNORGLIDE® SMTL is a composite material of compounded PTFE, bronze stretchedmetal and steel backing. In contrast to NORGLIDE® SM, the bronze stretched metalin NORGLIDE® SMTL is separately precompressed and the PTFE compound tape isthinner, which improves load capabilities while reducing tolerance compensationcompared to NORGLIDE® SM. Bearings of 0.75 mm of wall thickness or bigger canbe produced with an interference fit in the housing. Various methods are availableto protect the steel shell from corrosion (page 28).

AvailabilityThe standard PTFE compound contains either Ekonol® graphite or carbon and gra-phite. Special PTFE compounds are available on request. Fabricated parts include die-cuts, rolled cylinders, flanged cylinders and deep-drawn bearings.

NORGLIDE® SMTL

Standard thickness table NORGLIDE® SMNom. Material Structurethick-ness (mm) CuSn 6/Stretched metal

Steel backing0.75 ö

1.00 ö

1.50 ö

Standard thickness table NORGLIDE® SMTLNom. Material Structurethick-ness (mm) CuSn 6/Stretched metal

Steel backing0.50 ö

0.75 ö

1.00 ö


PTFE compound

Stretched metal

Steel backing

PTFE compound

Stretched metal

Steel backing

9

Material properties Norglide® SMSG Test Procedure Units Value







Material properties Norglide® SMTLSG Test Procedure Units Value


Coefficient of friction at RT on steel with ≥ 58 HRCat 4.8 N/mm2 and 0.058 m/s SG PL 0003 0.15at 70 N/mm2 and 0.0065 m/s SG PL 0003 0.10



K factor at RT on steel with ≥ 58 HRC SG PL 0003 10-6mm3/Nm 0.10


NORGLIDE® T Maintenance free bearing with metal backingNORGLIDE® T is a composite material of compounded PTFE tape on a metal shell. Thismaterial structure enables machining of the bearing in the housing – which is analternative to the sizing process - to obtain tightest tolerances on the inside diameter.

The very thick PTFE layer isolates noise and allows the design of clearance free bea-rings. Bearings of 0.75 mm thickness or bigger can be produced with an interferencefit in the housing. Various methods are available to protect the steel shell from corro-sion.

AvailabilityThe standard PTFE compound contains carbon and graphite. Special PTFE com-pounds are available on request. Finished parts include rolled bearings with orwithout an axial flange (nominal thickness 0.5 mm and 0.75 mm), deep-drawn bear-ings and die-cuts. The metal backing is available in steel, aluminum or even stain-less steel for chemically harsh environments.

NORGLIDE® T

NORGLIDE® PRO Maintenance free bearing with steel backingNORGLIDE® PRO is a steel material with a polygon-structured bronze layer on oneside. Encapsulated in the polygon structure is a sliding layer of compounded PTFEtape. This combination of materials provides much higher load-carrying capabilities.

The material is sizable and can be adapted to any clearance required for the specificapplication. The whole range of NORGLIDE® PRO thicknesses can be designed with apress fit in the housing. Several methods are available to protect the metal backingfrom corrosion.

AvailabilityPTFE compounds are available with carbon or EKONOL®. Fabricated parts includerolled bearings with or without an axial flange, deep-drawn bearings and die-cuts.

NORGLIDE® PRO

Standard thickness table NORGLIDE® TNom. Material Structurethick-ness (mm) Steel Stainless steel Alu

0.50 ö ö

0.75 ö ö ö

1.00 ö ö ö

1.50 ö ö

2.00 ö

Standard thickness table NORGLIDE® PRONom. Material Structurethick-ness (mm) Steel

0.50 ö

0.75 ö

1.00 ö


PTFE compound

Bronze

Steel

PTFE compound tape

Metal backing

11

Material properties Norglide® TSG Test Procedure Units Value




Maximum continuous operating temperature SG PL 0048 °C 180 to 260



Material properties Norglide® PROSG Test Procedure Units Value

Maximum permissible specific bearing load at RT SG PL 0044 N/mm2 400






Pure (virgin) PTFE is a soft, electri-cally insulating material with aminimum coefficient of frictionfor solid materials.

With the addition of fillers, pro-perties like creep or electrical con-ductivity can be optimized whilemaintaining the excellent slidingcharacteristics of PTFE.

Some of these compounds are dis-cussed here:

Compounds


Glass fiber/graphite CompoundGlass fibers increase the load carrying capability and reduce wear and creep.Graphite minimizes initial wear.

Carbon/ graphite Compound Carbon assumes a similar function as glass fibers, but is less abrasive on the matingcontact surface.

EKONOL® Compound This compound combines the outstanding wear resistance of EKONOL® with thelow initial wear of graphite. It is less conductive than the carbon/graphite com-pound.

Electrically Conductive Compounds With the addition of selected fillers we can tailor the electrical conductivity of thebearing. The total electrical resistance depends on the contact surface between thebearing and shaft, size, active surface load and the material thickness.

Electrically conductive bearings are used for electrostatic discharge, not for conduc-ting electrical current. They are most valuable in the cathodic dip-coating of assem-blies

Non-Conductive Compounds Electrically non-conductive bearings reduce paint build-up on the bearing surfacesand help improve paint quality.

a7258993

Schreibmaschinentext

a7258993

Schreibmaschinentext

13

U (m/min)10 10 -1 10 -3 10 -5

0,17 0,017 0,00017 0,0000017

0

0,1

0,2

Coef

ficie

nt o

f fric

tion

µ dy

n

p (MPa)

3,1

6,2

0,62

PTFE/Steel 100 Cr6

T= 23°CT= 70°C

m/sec

The coefficient of friction of a composite material is not a constant. It is dictatedby the materials of the mating contact surfaces and by the roughness of the har-der one. With combinations that have very different strength values (such as poly-mer with steel) the coefficient of friction also depends on the load. In addition,due to the polymers’ strong tendency to change all mechanical properties undertemperature, the coefficient of friction is also affected by speed and ambient tem-perature. The above shown graph demonstrates the influence of speed and loadon the coefficient of friction of a PTFE/steel bearing (100 Cr6 1.3505). The coeffi-cient of friction drops as load increases and as speed decreases. It also changes asthe bearings wear.

During the wear-in period NORGLIDE® bearings are shortly exposed to higherwear. A polymer transfer layer forms on the metal contact surface.

After wear-in a relatively constant performance range is found which is controlledby the pure PTFE compound layer.

With bronze reinforced NORGLIDE® types, the coefficient of friction increasesslightly after prolonged service due to the exposure of bronze to the mating sur-face. The bronze may then have contact with the shaft. This factor should betaken into account when selecting materials for applications with higher admis-sible wear or high pressure.

The coefficient of friction of NORGLIDE® T stays constant over the whole servicelife. With NORGLIDE® PRO XL the bronze layer can be reached after a short periodand the coefficient of friction grows gradually.

Generally speaking, the coefficient of friction of NORGLIDE® materials is outstan-dingly low in comparison with other polymer bearings, due to the use of PTFE asmain component in the bearing surface.

According to Research Report 83,Bundesanstalt für Materialprüfung,Berlin July 1982

Coefficient of friction


Life expectancy of NORGLIDE®bearings

Equation 1

Graph C

Graph A

Graph B

For some bearing materials pU limiting curves exist. In addition to these, parame-ters typical of the particular application (bearing clearance, roughness and hardnessof the mating-contact surface, ambient temperature, etc.) affect the position of thepU limiting curve.

pU = p · U

Specific bearing load p and sliding speed UThe life expectancy of NORGLIDE® bearings is essentially dictated by the environ-ment of the particular application. Simply stated, the life expectancy is derterminedby the specific bearing load p [N/mm2] and the sliding speed U [m/s] of the applica-tion range. The product of both values is called pU (pV).

In principle, NORGLIDE® bearings canbe used below the curves shown ingraph A. Oscillating motions, intermit-tent operation, oil lubrication or lowdemands on the life expectancy canachieve higher limit values.The static maximum bearing load de-pends on the material and describesthe maximum possible load the bea-ring can bear without sliding motionbefore it is destroyed. When designingthe pivot point, the deformation of thebearing by this load is to be taken intoaccount. Due to the visco-elastic beha-vior deformation depends on nominalforce, time and temperature (see graph B).The dynamic maximum bearing loaddefines the load limit for the applica-tion (sliding speed > 0) above which the bearing probably should not beused. The load limit also depends onthe sliding speed (see graph A). The permissible load decreases as thesliding speed increases.The pU limiting curves shown herehave been determined with conti-nuously rotating shafts in stationaryNORGLIDE® bearings. The pU operatingrange increases as the energy genera-ted by friction and ambient tempera-ture is absorbed by adequate cooling.

NOTE: pU = pV

0 50 100 150 200 250

1.2

1.0

0.8

0.6

0.4

0.2

0.0

K T

Temp [°C]

1000

100

10

1

0.1

Load

[MPa

]

0.001 0.01 0.1 1 10

Speed [m/s]

T-carbon/graphite

M-glass/graphite

PRO

MP

50

45

40

35

30

25

20

15

10

5

0

Defo

rmat

ion

[µm

]

0.01 0.1 1 10 100 1000 10000

Time [h]

30 M Pa, 23 °C100 M Pa, 23 °C30 M Pa, 100 °C

100 M Pa, 100 °C

TemperatureGraph C shows the influence of tempe-rature on the life expectancy which is40 % lower if the bearing is exposed,for instance, to a temperature of 100°C(correction factor KT).

15

Same applies to roughness values wellabove Ra = 0,4 µm.Low Ra values (Ra < 0,1 µm) lead to in-creased wear as well.

Load typeDynamic loads, i.e. loads alternating insize, reduce the life expectancy of thebearing. This fact is taken into accountwhen determining the dynamic factoror correction factor for the dynamicload Kdyn. For correcting the life expec-tancy under dynamic load, refer tograph F and proceed as follows:

1. Select the number of required load cycles

2. Read Kdyn

3. Use Kdyn for calculating the life expec-tancy

For applications without dynamic load,use Kdyn = 1 (uniform load).

With radial bearings, distinction is alsomade between point load and periphe-ral load, depending on whether theload is applied in a single point or isrotational. This influence is considered incorrection factor Kf :Point load Kf = 1Peripheral load Kf = 2

Graph D

Graph E

Graph F

Mating-contact surfaceLife expectancy is influenced also by parameters such as material (table 1), hardness(graph D) and roughness (graph E) of the mating-contact surface.Adverse values of hardness and roughness promote early wear, i.e. life expectancyof a bearing is substantially lower if shafts with a hardness value well below 50 HRCare used.

Shaft material KJ, MatSteel 1Low-corrosion steel 1Hard-chrome plated steel 1,5Gray cast iron 1Hard-anodized aluminum 1

Table 1

20 30 40 50 60

1.2

1.0

0.8

0.6

0.4

0.2

0.0

K J,H

RC

Hardness [HRC]

0.0 0.2 0.4 0.6 0.8 1.0

1.2

1.0

0.8

0.6

0.4

0.2

0.0

K J,R

a

Ra [µm]

103 104 105 106 107

1.2

1.0

0.8

0.6

0.4

0.2

0.0

K dyn

Load cycles


Bearing material hmax [µm] Kw [10-6 mm3/Nm] NORGLIDE® MP 280 0.12 - 0.18NORGLIDE® M 280 0.12 - 0.18NORGLIDE® SM 250 0.16 - 0.70NORGLIDE® SMTL 100 0.10NORGLIDE® T 250 0.10 - 0.90NORGLIDE® PRO 100 0.18 - 0.20

Kf Correction factor load typeKdyn Correction factor dynamic loadKT Correction factor temperatureKJ,HRC Correction factor hardnessKJ,Ra Correction factor roughnessKJ,Mat Correction factor shaft material

tmax = · Kf · Kdyn · KT · K J,HRC · KJ,Ra · KJ,Mathmax

Kw · pU · 3.6Equation 2

Equation 7

Equation 3

Equation 4

Determining the specific bearing load

Determining the sliding speed (bush, washer):

p = FD · B

p = 4 · Fπ · (D0

2 - Di2)

Equation 5

Equation 6

U = π · D · N60 · 103

U = xπ · D60 · 103

2 · ϕ · Nosc

360

tmax =∑ · tmaxiti

tcycle

With the above mentioned parameters and the related correction or wear factorsthe life expectancy can be calculated by the following equation:

Table 2

Life expectancy of NORGLIDE® bearingsWear depth ( ∆hmax) andwear factors (KW factor)The two wear sizes described in thischapter depend on the material orsystem used. Wear depth ∆ hmax is thethickness of the bearing layer which,when worn, indicates the end of thebearing life. Wear factor is the volumeper energy unit (load and sliding dis-tance) worn by the application. Themaximum permissible wear depths ofselected bearings materials and therelated wear factors are listed in table 2.

Life expectancyThe influences described here havebeen calculated empirically and otherunconsidered factors typical of the par-ticular application may be of impor-tance. Therefore, the theoretically cal-culated life expectancy of NORGLIDE®bearings is an estimate rather thanexact value and should be verified inpractical tests for the individual appli-cation.

Determining the nominal life expectancy for operationunder alternating stressDetermining the nominal life expectancy for operation under alternating stress tmax

is calculated by classifying loads and sliding speeds in groups within which bothsizes are approximately constant. tmaxi , the maximum life expectancy of each class,is calculated, and then factored with the frequency of occurrence. The total of facto-red individual results corresponds to the maximum life expectancy of the bearing.

17

The speed is calculated per equation 5:

The calculation of the specific bearing load p per equation 3 results in:

Now the pU value can be determined with equation 1:

p = FD · B p = MPa

100012 · 8 p = 10.42 MPa

pU = 0.17 MPa · m/spU = 10.42 · 0.016 MPa · m/spU = p · U

The required life expectancy is exceeded. NOTE: pU = pV

By increasing the nominal width B (to 10 mm) p and pU can be reduced and hencethe nominal life expectancy be increased.

p = MPa100012 · 10 p = 8.33 MPa

pU = 8.33 · 0.016 MPa · m/s pU = 0.13 MPa · m/s

tmax = · 1 · 1 · 1 · 1 · 1 · 1 h150

0.18 · 0.13 · 3.6 tmax = 1781 > tmax, required = 1500 h

The life expectancy can be determined with equation 2:

KJ,HRC = 1 (steel: 55 HRC)

KJ,Ra = 1 (Ra= 0,2µm)

KJ,Mat = 1 (steel)

Kf = 1 (lumped load)

Kdyn = 1 (uniform load)

KT = 1 (temperature 30°C)


Kw · pU · 3.6

tmax = · 1 · 1 · 1 · 1 · 1 · 1 h150

0.18 · 0.17 · 3.6 tmax = 1362 < tmax, required = 1500 h

A verification of the p, U and pU values for suitability (graph A) demonstrates thatthey are within the recommended range.The following values are determined as correction factors:

U = · m/sπ · 1260 · 103

2 · 60 · 75360 U = 0.016 m/sU = xπ · D

60 · 103

2 · ϕ · Nosc

360

Known data:Nominal bearing D 12 mmdiameterNominal bearing width B 8 mmBearing load F 1000 NSlewing frequency Nosc 75 min- 1

Slewing angle ϕ 60°Ambient Tamb 80 0Ctemperature

Example 1:Oscillating motionA bearing is to be manufactured withNORGLIDE® M. The shaft is made ofhard steel (55 HRC) with a surface finishRa=0,2µm. Required life expectancy:1500 h. Load: uniform, in one direction.Maximum permissible radial wear:150 µm. To be determined is the maxi-mum life expectancy

Calculation of life

expectancy

Calculation of life expectancyExample 2: Rotary motionA bearing is to be manufactured withNORGLIDE® SM. The shaft is made ofhard steel (55 HRC) with a surfacefinish Ra=0,2µm. Required life expec-tancy: 1000 h. Load: uniform, but rotary.Maximum permissible radial wear:250 µm.Question: Is it possible to reduce thenominal bearing width?

The speed is calculated per equation 5:

The calculation of the specific baring load p per equation 3 results in:

Now the pU value can be determined with equation 1:

p = FD · B p = MPa

200025 · 15

U = m/sπ · 25 · 3160 · 103

p = 5.33 MPa

pU = 0.22 MPa · m/spU = 5.33 · 0.041 MPa · m/spU = p · U

U = π · D · N60 · 103 U = 0.041 m/s

The required life expectancy is reached.The nominal bearing width can be reduced from 15 mm to 10 mm.

The nominal bearing width is related with the life expectancy so that a reduction byone third (to 10 mm) is possible.

p = MPa200025 · 10

p = 8.00 MPa

pU = 8.00 · 0.041 MPa · m/spU = p · U pU = 0.33 MPa · m/s


Kw · pU · 3.6

tmax = · 2 · 1 · 0.7 · 1 · 1 · 1 h250

0.24 · 0.33 · 3.6 tmax = 1228 > tmax, required = 1000 h

p = FD · B

Calculation of life expectancy per equation 2:

Kf = 2 (peripheral load)

Kdyn = 1 (uniform load)

KT = 0,7 (temperature 80°C)

KJ,HRC = 1 (steel: 55 HRC)

KJ,Ra = 1 (Ra= 0,2µm)

KJ,Mat = 1 (steel)


Kw · pU · 3.6

tmax = · 2 · 1 · 0.7 · 1 · 1 · 1 h250

0.24 · 0.22 · 3.6 tmax = 1841 >> tmax, required = 1000 h

A verification of the p, U and pU values for suitability (graph A) demonstrates thatthey are within the recommended range.

The following values are determined as correction factors:

A verification of p, U and pU values for suitability (graph A) demonstrates that they are withinthe recommended range.

Known data:

Nominal bearing D 25 mmdiameter

Nominal bearing width B 15 mmBearing load F 2000 NSlewing frequency Nosc 31 min- 1

Ambient Tamb 80 0Ctemperature


19

Calculation data and units (ISO 7904)

Nominal width of bearing (length) B [mm] Nominal diameter of bearing D [mm]Inside diameter of washer’s Di [mm]retaining ring

Outside diameter of washer’s D0 [mm]retaining ring

Max. permissible radial wear ∆hmax [µm]K-factor Kw [10-6mm3/Nm]Bearing load F [N]Rotational frequency N [min-1]Slewing frequency Nosc [min-1]Specific bearing load p [MPa]pU value pU [MPa · m/s] Wall thickness s [mm]Ambient temperature Tamb [0C]Max. life expectancy tmax [h]Duration of approximately constant ti [h]pU conditions within the load cycle

Duration of load cycle tcycle [h]Max. life expectancy at approximately tmaxi [h]constant pU conditions within the load cycle

Sliding speed U [m/s]Slewing angle ϕ [°]


The life expectancy of a bearing is very much dependent on its design where factorslike load, dimensions, material selection, surface finish and geometry have to betaken into consideration.

In many cases the dimensions of a bearing are dictated by the design environment.An estimate of the life expectancy can determine which NORGLIDE® type is capableof bearing a given load. If necessary, the pivot point has to be modified accordingly.Requirements on the tribological properties and the knowledge of influences bythe bearing environment help to select the proper NORGLIDE®material.

Practically, the mating or contact surface can be made of any steel or plastic. Betterperformance is achieved with surfaces in a hardness range of 50 to 60 HRC. Theuse of plastics is, therefore, limited to a few isolated cases, whereas the selection ofmetals focuses on various steel grades.

Another factor vitally important for the life expectancy of a bearing is the surfacefinish. Sharp elements in the surface – even if tiny – can never be avoided in machinedparts. It is therefore recommended to choose drawn, rolled or milled surfaces.Polished surfaces produce erosion damage and are not ideal contact surfaces. Forslowly oscillating movements, the value of mean surface finish Ra should range bet-ween 0.15 - 0.80 µm, for high frequency oscillating and rotating movement, it shouldbe in between 0.15 - 0.35µm. Corrosion alters the surface roughness appreciably andhence increases wear so that suitable protection methods or a corrosion-resistantsteel should be used. In extremely dirty environments, the bearing should be pro-tected with proper sealing systems.

Housings should have chamfers according to DIN 3547 to ease the installation ofbearings. The pins or shafts should be designed with a radius to avoid damage tothe bearing surface during installation.

Design of the bearing

21

TolerancingNORGLIDE® bearings are designed for either a heavy press fit into a housing or to beinserted by hand. Bearings designed for hand insertion are usually flanged bearingsthat require a secondary flange to retain the bearing in the housing.See the “Installation of the bearings” section for more detail on this. The housing to-lerance has a direct linear relationship to the mounted bearing ID tolerance. This to-lerance can be reduced by sizing the ID of the bearing after installation. The “Sizing”section covers this capability in detail.

Clearance fits (between bearing and pin)The tolerance field on the inside diameter is controlled by the tolerance on the boresize and the tolerance of the NORGLIDE® bearing. With some material types the to-lerances between pin and inside diameter of the bearing can be adapted by sizing(see page 22). This procedure allows producing a new bearing inside diameter with acloser tolerance range. Extremely tight clearance fits can be obtained by using ade-quately toleranced pins (min. h7). For rotary motions, linear sliding motions or highfrequency oscillating motions the minimum clearance should not be less than 0.015to 0.020 mm.

Interference fits (between bearing and pin)NORGLIDE® materials offer the opportunity to design clearance free bearings. Forthis purpose the combination of pin/NORGLIDE® bearing/housing is selected in away that always interference is obtained. This interference is possible, becauseNORGLIDE® materials have an extraordinary thick PTFE layer which provides elastici-ty. When installed, this elasticity exercises back pressure onto the pin and hence pro-duces a torque in slewing motions and isolates noise. Sizing and accurately toleran-ced pin diameters make it possible to limit the torque. After sizing the interferenceshould not be more than 0.01 mm including consideration of wear.

Sizing for clearance-fitIn addition to the permanent deforma-tion of the radial wall thickness of aNORGLIDE® bearing, an elastic defor-mation is to be taken into considera-tion when sizing. Consequently, the in-side diameter resulting from a sizingstep is always smaller than the diameterof the sizing pin. Therefore, to ensure apermanent clearance fit between bea-ring and pin, sizing beyond the targetis needed. After this, due to the plasticrecovery of the sliding layer, the finalinside diameter is achieved.

What is sizing?NORGLIDE® bearings are made of compo-site materials.The individual componentsdisplay a more or less developed plasticand elastic deformation capability. Plasticdeformation is used for sizing, i.e. alteringthe sizes to a certain degree.The materialcan be formed by sizing with tools (usual-ly a sizing pin). By sizing the bearing in theoriginal housing, the overall tolerancerange (tolerance of housing + tolerance ofbearing material) can be very much redu-ced.This allows for wider production tole-rances and the associated cost benefits.Sizing allows for an increase of the inside

Sizing for interference-fitDepending on the NORGLIDE® materialbegin with an interference of 0.150 to0.250 mm. After sizing, the maximuminterference on the pin to be mountedshould not exceed 0.010 mm. Thisinterference is important if, forinstance, a torque is to be generated ina hinge. The suitable modification ofhousing and/or pin allows to designany fit between clearance-fit and inter-ference-fit.

Design of sizing pinsThe geometry of sizing pins is describedon page 24 Detail „Y“. For the purpose ofthis study, only the active sizing range ofa sizing pin will be examined in detail.To calculate the pin’s diameter deducttwice the largest NORGLIDE® thicknessfrom the smallest housing size. Add thevalue of 0.05 mm to this calculated bea-ring inside diameter to have the diame-ter of the first sizing pin. Sizing shouldtake place in maximum steps of 0.06mm to prevent damage to the bearingsurface. Each sizing step should be madein both directions to prevent delamina-tion of the bearing layer. It is not recom-mended to combine several sizing stepswith the aid of a multi-step mandrel.

diameter of the installed bearing by up to0.150 mm, depending on the length of thepivot point and the material type.NORGLIDE® materials with metal fabricor stretched metal are ideal for sizing. Asteel backing limits the sizing capability oflonger bearings. NORGLIDE®-PRO typesare also sizable due to the PTFE tapewhich is encapsulated in the polygonstructure. Sizing alters mainly the radialthickness of the bearing material. At thesame time the bearing increases inlength. This increase in length dependson the NORGLIDE® type and the amount

of sizing and has to be deducted whendesigning the bearing, otherwise the secondary flange will be too large.NORGLIDE® T is the only product with alimited sizing capability.When sized, thebearing material adapts to the surface ofthe housing wall and hence reduces thetolerance range.

Sizing


0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 0.11 0.12

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

Torq

ue [N

m]

Interference after sizing [mm]

Torques are dictated by the coefficient of friction, pressure, friction surface, speedand finish of the rubbing-contact surfaces.

In contrast to the Coulomb law of friction, the coefficient of friction depends onboth pressure and sliding speed. Therefore, no universal value can be given (seepage 13).

For some applications, particular torques are specified. The material composition ofNORGLIDE® MP, S, M, SM and SMTL is such that an interference fit between the pinand the bearing’s inside diameter (see page 21) is designed to produce torque.

The pressure depends on the pin’s interference with the inside diameter of thebearing. This pressure in the cylindrical (radial) part of the bearing produces thetorque. With flanged bearings additional (axial) torque may be produced if pressureis exerted on the flanged surfaces. By appropriate changes in the design, such asproper adjustment of the riveting shoulder height, effects can be influenced in theaxial direction. Another factor that influences total torque and should be conside-red in the design is the riveting process.

Only the torque produced in the radial part of the bearing will be examined indetail. The following test with NORGLIDE® MP may serve as an example: With abearing length of 19.3 mm and a pin diameter of 8.00 mm the range of interferencewas varied between 0.02 mm and 0.08 mm. Torques in the range of 0.3 N to 1.4 Nwere reached.

Interferences > 0.08 mm should not be used to prevent damage to the bearing sur-face. Unevenly spread wear of the sliding layer may lead to an uncontrolled increaseof the torque. Strong pre-stress may reduce the life expectancy of the bearing.

The following factors should be taken into account:

• The torque values should not be too high.• Due to the material’s recovery the torque increases after installation.• When a bearing with high interference between the bearing’s inside diameter

and the pin is exposed to temperatures > 200°C over a longer period, unstressingof the PTFE layer is noticed. The torque drops accordingly.

Due to the vast variety of parameters that influence torque, the values retained forthe torque range should be verified in practical tests for the individual application.

23

Torques

Continuous torque as a function of interference, exemplified by Norglide® MP(qualitative illustration)

The process described below is some-what idealized, but includes the mostimportant steps for installing NORGLIDE®bearings into a housing. If and in whichorder the individual steps have to bemade depends on the material type,the application and the technical feasi-bility and should be discussed with ourapplication engineers.

How to feed the bearing to the installation pointThe degree of automation decides on whether the bearing is inserted by hand orby machine. With tangle-free bearings, a combination of vibration feeder and grip-per can be used. Long distances between feeder and installation point are overco-me by „shooting“ the bearing pneumatically through a profile tubing.

How to insert the bearing into the housingBearings with a loose fit in the housing do not necessarily need a mandrel forinstallation. If a mandrel is used, calculate its diameter by deducting twice* the lar-gest NORGLIDE® thickness from the smallest inside diameter of the housing; thendeduct the value of 0.05 mm. (*takes three times the largest NORGLIDE thicknessin the case of a MP bearing with overlap). Details of a mandrel design to accom-plish press fit of the bearing are shown in the drawing.

How to prevent movement of the bearingTo prevent bearing movement during all subsequent forming operations, so-called“downholders“ are used which grip the axial flange and fix the bearing. A „deadstop“ (spacer) prevents squeezing of the flange (see Detail Z).


Installation of

NORGLIDE® bearings

Detail "X"

Detail "Y"

Detail "Z"

Pressing in Sizing

Y

F F

dead stop

Downholder

Chamfer

Dead stop

75%

Nom

inal

bea

ring

leng

th

How to size the inside diameterThe possibilities of modifying the bearing's inside diameter by sizing were discussedin detail on page 22. The sizing pin must have all transitions designed with radii asshown in Detail X. Its active sizing range must be hardened and polished. Additionaltapering of the pin may ease lead-in.

How to form the 2nd flange in one or two stepsUsually flanging is done in two steps: 1st step: 45°; 2nd step: 90°. In particular cases, ifthe geometry of housing and pin allows, the 2nd flange can be formed in a singlestep, but it will be narrower than a flange formed in two steps. This must be conside-red when designing the bearing. Also in this case all transitions must be designedwith radii (Detail Z) and the active sizing range must be hardened and polished.Additional tapering may ease lead-in. A „dead stop“ prevents squeezing of the 1stand of the 2nd flange (Detail XYZ).

25

Pre-flanging Final flanging

X

R = Material thickness + 0.5

X

Z

R = Material thickness + 0.75

Downholder Downholder

Drawings for NORGLIDE® fabrica-ted parts do not only describethe dimensions of the bearing,but also state the measurementmethods used.

Measuring NORGLIDE® bea-rings without steel backingThis group of bearings is made of flexi-ble materials. A master gauge is used tomake sure the measurements are re-producible and comparable. To performthe measurement, the NORGLIDE® bea-ring is inserted into a ring gauge.A plug gauge descends into the bearingand ensures it has a firm seating andoptimum roundness. The gauge is flat-tened on one side and has one or twoinspection windows. A gauge pin isused to determine the gap size X. Themaster gauge is designed to measureboth the length of the bush and themaximum permissible flange diameter.

Measuring NORGLIDE®bearingsMeasuring NORGLIDE® bearings with steel backingThe diameter measurement is performed on the basis of the methods described instandard ISO 3547-2. These are:

Test A per ISO 3547-2This method for testing the outside diameter can be carried out on all bushingsthat have an interference fit to the housing’s inside diameter. This means, it is onlysuitable for NORGLIDE® bearings with steel backing > 0.5 mm and for all PRO types.

With the gap up, the bushing is inserted into the master gauge. Using a given testforce the two shell halves are pressed together so that the bushing is exposed to apre-stressing force in the elastic range. Determined is the deviation of distance z(from a standard value) between the shell halves. The exact procedure and evalua-tion of this method - which is known also as ∆z test - is described in detail in ISO3547-2.

Test B per ISO 3547-2This simplified method for testing the outside diameter can be carried out on allNORGLIDE® bushes with steel backing and on bearings with and without a flangeregardless of the material thickness.

The test uses GO and NO GO ring gauges. The GO gauge must take up a NORGLIDE®bearing when pressed in by hand. The NO GO gauge must not accept the bearingwhen pressed in with the same force. The diameters of the gauges are selectedaccording to standard 3547-1.

In this GO gauge, the flange diameter can be tested.

Test C per ISO 3547-2This method is used for testing the inside diameter. It can be carried out on allNORGLIDE® bushings with steel backing and on bearings with and without a flangeregardless of the material thickness.

The test uses a gauge. In this master gauge the inside diameter of the bearing canbe tested with plug gauges. The GO plug gauge should fit with a minimum of force.The NO GO plug gauge must not fit by hand. The fitting forces and diameters ofthese plug gauges have to be agreed upon with the user.


27

Measurement gages for ∆z


Corrosion resistanceThe NORGLIDE® bearing steel shell can be provided with an anti-corrosive coatingcombined of zinc plating, Cr6 free passivation and sealing, depending on what kind ofprotection is needed. In a few special cases, other corrosion-protection systems can beused to avoid contact corrosion. All systems comply with the European Union End-of-Life directive for automotive vehicles 2000/53/EG.

In comparison with components of solid refined metal, specially structured NORGLIDE®bearings have a shorter corrosion resistance when exposed in the salt spray chamber.The corrosion resistance of the individual components is not necessarily identical withthe life expectancy of the assembly. For choosing the proper anti-corrosive coating,the composition and operating conditions should also be taken into account. Actualcorrosion resistance should always be verified in the assembled condition.

Some NORGLIDE® types use a stainless steel backing and do not need additional cor-rosion protection. Some NORGLIDE® types use a backing of aluminum which alsodoes not require further protection because it passivates itself. In both cases howeverthe electro-chemical chain must be taken into account to prevent contact corrosion inthe assembled condition.

Flexible NORGLIDE® variants are reinforced by mesh or stretched metal structures oftin/bronze CuSn6 (material No. CW452K), of stainless steel FeCr18Ni10Mo3 (materialNo. 1.4401), of aluminum AlMg3 (material No. 3.3536) and do not need additional cor-rosion protection. Also in this case the electro-chemical chain must be taken intoaccount to prevent contact corrosion.

The resistance to red and white corrosion of NORGLIDE® bearings is tested to DIN ENISO 9227 during production in our own salt spray chamber. In special cases the saltspray test is conducted on parts in the assembled condition.

29

Salt Spray Chamber

Integrated Management

Quality… we team with our customers:

All quality related criteria of NORGLIDE® bearings are established with the custo-mer in our NORGLIDE® drawing.

… we achieve certifications:

Our modern quality management complies with international standards. Certifi-cates are provided on request.

… we plan quality:

With our quality preplanning systems we identify and plan all criteria and theirrisks - from the drawing board to delivery.

… we inspect and test quality:

Alongside our reliable production processes and statistical process control techni-ques, our highly trained staff is responsible for a continuous improvement pro-gram in compliance with the Six Sigma philosophy.

EHSEnvironment, Health and Safety

… we ensure compliance:

While considering environmental protection as a key element our company is com-mitted to maintaining health and safety, because health and motivation of our staffare the core of highly efficient performance.

… this means to our customers:

We are, and will remain, an attractive, highly reliable partner for sustained success.


Quality, Environment, Health and Safety (QEHS) Policy

Future by sustainability In order to sustain our company's success

• We focus on the protection and the inviolacy of employees and environmentand on complying with customers' requirements.

• We accompany new developments with integrated QEHS concepts.

• We pursue a zero-defect strategy in all departments.

• We take care of our products all the way from the technical concept to the start of production at our customers.

• We want to exceed our employees' and our customers' expectations.

In order to assure this sustainability

• We set QEHS and economic goals and evaluate achievement.

• We provide capable, controlled and reliable processes and procedures while steadily reducing the distribution (6σ).

• We continuously improve our products, our processes and our managementsystem.

• We prevent defects and accidents by suitable programs.

• We strictly comply with the requirements made by customers, norms and laws.

• We have our management system certified and audited according to ISO/TS 16949, DIN EN ISO 14001 and OHSAS 18001.

• We involve our suppliers into our QEHS activities.

In order to be able to achieve our goals

• We promote high-level qualification and a definite sense of responsibility of our employees by continuous training and education.

• We reduce environmental and health hazards for our employees by using modern technologies.

• We minimise our consumptions to preserve natural and corporate resources.

• We regularly check, monitor and evaluate the results of our activities.

• We work in interdisciplinary teams.

The Saint Gobain Performance Plastics Pampus GmbH management team

31


Practical ApplicationDoor hinge

Seat adjustment systems

Two-mass fly wheel

Belt tensioner

Decoupled pulley

Steering gear

Pedal linkages

Light projection range adjustment

Shock absorber

Front hood hinge

Trunk hinge

Windshield wiper

Brake lever

Automatic mirror adjustment

Steering column adjustment

3

14

4

12

5

11

13

2

109

8

6

1

15

7

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Two-mass fly wheel

Pedal linkages

Shock absorber

Belt tensioner

Sliding door

Flap hinges

Hinges

33

Convertiblesystems

ValvesSwivel drive

Expansion groove

Door hinge

Ball joint

Pump

Front shock absorber

Rear shock absorber

Pivot points rear shock absorber

Pivot points rear shock absorber

1

2

3

4

123

4

AUMA Riester GmbH & Co. KGCampagnoloCR Hammerstein Dr. HahnEdschaGAT Gesellschaft fürAntriebstechnik mbHISE Innomotive Systems Europe GmbH Kirchhoff GmbH & Co. KGLitens Metso Automation Maurer Söhne GmbH & Co.KG SRAMTrek ZF Sachs AG

Seat mechanism

Bicycle brake

Practical Application


We thank the following companies for thephotografic material provided:

www.bearings.saint-gobain.com

BSTE

-415

4R-5

K-12

09 ©

Sain

t-Gob

ain

Perfo

rman

ce P

last

ics

Warranty: The data and information in thiscatalogue or in our web sites are not bindingand were correct and up-to-date at the timeof release. Technical modifications and deve-lopments as well as adaptations to complywith amended standards, norms and guideli-nes can be made without notice. The productcharacteristics, especially load bearing capa-bility and wear, depend on the applicationand the environment the product is used in.Therefore the data does not assure specificproduct characteristics or make reference tothe suitability of the product for a definite orfictitious application. In case of new applica-tions users must test the product underthese actual application conditions and theapplication should be discussed with themanufacturer. Within the scope of law anyliability for us, and all those acting on ourbehalf, for the data and information in thiscatalogue or in our web sites shall be exclu-ded. Any contracts are concluded on the basisof our General Business Terms and Condi-tions, which could be downloaded from ourweb site, or forwarded to you as requested.

NORGLIDE®, NORSLIDE® and RENCOL® are registered trademarks of the Saint-Gobain Group of Companies.

Saint-Gobain do BrasilLtda.Vinhedo-SP • BrazilPhone: (55) 192127 8534Fax: (55) 19 2127 8539

Saint-Gobain PerformancePlastics Shanghai Co. Ltd.Shanghai • ChinaPhone: (86) 2154 721568Fax: (86) 2154 725993

Saint-Gobain PerformancePlastics Pampus GmbHWillich • GermanyPhone: (49) 2154 600Fax: (49) 2154 60310

Grindwell Norton Ltd.Bangalore • IndiaPhone: (91) 802506 7508Fax: (91) 802847 2905

Saint-Gobain KK-Performance PlasticsSuwa, Nagano • JapanPhone: (81) 26679 6400Fax: (81) 26670 1002

Saint-Gobain PerformancePlastics CorporationSaltillo • MexicoPhone: (52) 844866 1200Fax: (52) 844 180 8213

Saint-Gobain PerformancePlasticsKontich • BelgiumPhone: (32) 34582828Fax: (32) 345826696

Saint-Gobain PerformancePlasticsSt Quentin Fallavier • FrancePhone: (33) 47494 8222Fax: (33) 47494 2341

Saint-Gobain PerformancePlasticsAgrate Brianza (Mi) • ItalyPhone: (39) 0396 57891Fax: (39) 0396 52736

Saint-Gobain PerformancePlasticsGarden Grove, CA • USAPhone: (1) 714-995-1818Fax: (1) 714-688-2701

Saint-Gobain PerformancePlasticsDetroit, MI • USAPhone: (1) 248 888 8010Fax: (1) 248 888 8015

For more information please call us.Alternatively email us at [email protected] or [email protected]

Manufacturing Sites

● BEARINGS SITES● SEALS SITES● SEALS & BEARINGS SITES

Sales Only Locations for Bearings

Saint-Gobain PerformancePlasticsKolo • PolandPhone: (48) 63 2617 100Fax: (48) 63 2617 232

Saint-Gobain PerformancePlastics Korea Co. Ltd.Seoul • South KoreaPhone: (82) 2508 8200Fax: (82) 2554 1550

Saint-Gobain AdvancedMaterials (Taiwan) Co. Ltd.Taipei • TaiwanPhone: (886) 2250 34201Fax: (886) 2250 34202

Saint-Gobain Sekurit(Thailand) Co. Ltd.Rayong • ThailandPhone: (66) 3866 78007Fax: (66) 38667 892

Saint-Gobain PerformancePlastics Rencol Ltd.Bristol • United KingdomPhone: (44) 117 9381700Fax: (44) 117 9157982

Saint-Gobain PerformancePlastics CorporationWayne, New Jersey • USAPhone: (1) 973 696 4700Fax: (1) 973 696 4056

innovation is our nature - saint-gobain · innovation is our nature maintenance free bearings •...

Documents