Internal clearance and operating clearance

Internal clearance and operating clearance

Operating clearance of spherical plain bearings

The operating clearance or preload is determined on a fitted bearing still warm from operation.

It is derived from the radial internal clearance and the change in the radial internal clearance as a result of interference fit and thermal influences in the fitted condition.

Internal clearance of radial spherical plain bearings

The radial and axial internal clearance is determined on the dismounted bearing.

The radial internal clearance of radial spherical plain bearings is defined as the distance by which the inner ring can be moved in a radial direction relative to the outer ring from one extreme position to the precisely opposite extreme position, ➤ Figure.

Maintenance-free spherical plain bearings

Maintenance-free spherical plain bearings have a very small internal clearance. As a result, preloads may be present once the bearing is fitted.

Spherical plain bearings requiring maintenance

The radial internal clearance is subdivided into three groups in accordance with DIN ISO 12240-1, see table. The precondition is a housing bore that causes no dimensional changes in the bearing with the exception of geometrical inaccuracies.

Radial internal clearance
Group 2 to Group 3 = internal clearance groups
Radial internal clearance groups

Internal clearance group in accordance with ISO 12240-1

Description

Application range

Group N

(CN)

Normal internal clearance; CN is not included in bearing designations

Under normal operating
conditions and with the rec­ommended fits, this gives optimum operating clearance

Group 2****

(C2)

Internal clearance < CN
(suffix C2)

For bearing arrangements
with very small clearance

Group 3

(C3)

Internal clearance > CN
(suffix C3)

For bearing rings with press fits or
a large temperature differential between the inner and outer ring

**Relubrication only possible with tilt angle α = 0°.

**Example of bearing with restricted internal clearance: GE220-DO-2RS-C2.

Radial internal clearance

Series

Radial internal clearance

μm

GE..-DO
GE..-DO-2RS(-2TS)
GE..-HO-2RS
GE..-LO

GE..-FO
GE..-FO-2RS(-2TS)

Group 2
(C2)

Group N
(CN)

Group 3
(C3)

Bore

d

mm

min.

max.

min.

max.

min.

max.

6

6

8

32

32

68

68

104

8

8

8

32

32

68

68

104

10

10

8

32

32

68

68

104

12

‒

8

32

32

68

68

104

‒

12

10

40

40

82

82

124

15

15

10

40

40

82

82

124

16

‒

10

40

40

82

82

124

17

17

10

40

40

82

82

124

20

‒

10

40

40

82

82

124

‒

20

12

50

50

100

100

150

25

25

12

50

50

100

100

150

30

30

12

50

50

100

100

150

32

‒

12

50

50

100

100

150

35

‒

12

50

50

100

100

150

‒

35

15

60

60

120

120

150

40

40

15

60

60

120

120

180

45

45

15

60

60

120

120

180

50

50

15

60

60

120

120

180

60

‒

15

60

60

120

120

180

‒

60

18

72

72

142

142

212

63

‒

18

72

72

142

142

212

70

70

18

72

72

142

142

212

80

80

18

72

72

142

142

212

90

‒

18

72

72

142

142

212

‒

90

18

85

85

165

165

245

100

100

18

85

85

165

165

245

110

110

18

85

85

165

165

245

120

120

18

85

85

165

165

245

140

‒

18

85

85

165

165

245

160

140

18

100

100

192

192

284

180

160

18

100

100

192

192

284

200

180

18

100

100

192

192

284

‒

200

18

110

110

214

214

318

220

220

18

110

110

214

214

318

240

‒

18

110

110

214

214

318

250

240

18

125

125

239

239

353

260

260

18

125

125

239

239

353

280

280

18

125

125

239

239

353

300

‒

18

125

125

239

239

353

Axial internal clearance

The axial internal clearance is defined as the distance by which the inner ring can be moved in an axial direction relative to the outer ring from one extreme position to the precisely opposite extreme position, ➤ Figure.

It is dependent on the bearing geometry and is in a direct relationship with the radial internal clearance. Depending on the bearing type, it may be several times greater than the radial internal clearance.

Axial internal clearance
sa = axial internal clearance

Fit conditions for spherical plain bearings

The interference fits and clearance fits for practical use are determined from the corresponding ISO fit in conjunction with the normal bearing tolerances in accordance with DIN ISO 12240-1 to DIN ISO 12240-3, see tables. The actual dimensions must correspond to the centre tolerance.

Definitions:

  • – indicates an interference fit
  • + indicates a clearance fit.
Shaft fits

Example:

  • A shaft of diameter ⌀50 m6 Ⓔ has a probable interference fit of 0,023 mm.
Interference fit ÜI or clearance fit

Nominal shaft diameter in mm

over

incl.

  3

  6

  6

 10

 10

 18

 18

 30

 30

 50

 50

 80

 80

120

120

180

180

250

250

315

315

400

400

500

Normal tolerance, interference fit or clearance fit in μm**

h6

0

0

+1

+1

+2

+2

+1

0

0

–2

–2

–2

j6

–6

–7

–7

–8

–9

–10

–13

–14

–17

–17

–20

–22

k6

–9

–9

–9

–14

–16

–20

–24

–28

–30

–33

–38

–42

m6

–12

–15

–17

–20

–23

–28

–34

–40

–47

–53

–59

–65

n6

–16

–19

–22

–27

–31

–37

–44

–52

–61

–67

–75

–82

**Not applicable to series GE..-LO, GE..-PB, GE..-SX, GE..-PW and GE..-SW.

Housing fits

Example:

  • A housing bore of diameter ⌀75 M7 Ⓔ has a probable inter­ference fit of 0,009 mm.
Interference fit ÜA or clearance fit

Nominal housing bore diameter in mm

over

incl.

 6

10

 10

 18

 18

 30

 30

 50

 50

 80

 80

120

120

150

150

180

180

250

250

315

315

400

400

500

Normal tolerance, interference fit or clearance fit in μm**

J7

+4

+5

+6

+7

+10

+12

+15

+18

+22

+27

+31

+34

K7

+1

+1

–1

0

0

–1

+1

+4

+5

+7

+8

+8

M7

–4

–5

–7

–8

–9

–11

–11

–8

–8

–9

–9

–10

N7

–8

–10

–14

–16

–18

–21

–23

–20

–22

–23

–25

–27

**Not applicable to series GE..-SX and GE..-SW.

Influence of interference fit

The radial internal clearance of radial spherical plain bearings changes due to the fit as a result of:

  • expansion of the inner ring
  • contraction of the outer ring.
ACHTUNG

If the remaining internal clearance of spherical plain bearings requiring maintenance is ≦ 0, a bearing of another internal clearance group with a larger internal clearance must be selected.

Factors for expansion or contraction
Factors for the cross-section:
b = inner ring · c = outer ring · f = factor for expansion of the housing
Expansion of the inner ring
a μm

Expansion of the inner ring when using solid shafts, measured on the sphere diameter

ÜI μm

Effective interference fit, see table

b–

Factor for the cross-section of the inner ring, see table, and ➤ Figure

0,9–

Factor for the roughness, ovality and unevenness of the supporting component surface.

Contraction of the outer ring
In the case of ring-shaped housings, expansion of the housing must be taken into consideration. The expansion is dependent on the wall thickness and is taken into consideration in the factor f:
e μm

Contraction of the outer ring, measured on the raceway diameter

ÜA μm

Effective interference fit, see table

f–

Factor for expansion of the housing, see link

0,9–

Factor for the roughness, ovality and unevenness of the supporting component surface.

Factor for the cross-section of the inner ring

Bore

d

Factor for series

b

mm

from

to

GE..-DO(-2RS), (-2TS)
GE..-HO-2RS
GE..-LO**
GE..-UK(-2RS), (-2TS)

GE..-FO(-2RS), (-2TS)
GE..-FW(-2RS), (-2TS)
GE..-PB**
GE..-PW**

6

10

0,65

0,55

12

20

0,72

0,64

25

70

0,79

0,71

80

140

0,8

0,75

160

300

0,84

0,78

**Interference fit ÜI not listed in the overview, see table.

Factor for the cross-section of the outer ring

Bore

d

Factor for series

c

mm

from

to

GE..-DO(-2RS), (-2TS)
GE..-HO-2RS
GE..-LO
GE..-UK(-2RS), (-2TS)

GE..-FO(-2RS), (-2TS)
GE..-FW(-2RS), (-2TS)
GE..-PB
GE..-PW

‒

6

0,7

‒

6

20

‒

0,81

8

25

0,81

‒

25

35

‒

0,83

30

40

0,83

‒

40

280

‒

0,85

45

300

0,85

‒

Calculation of the factor f for expansion of the housing

When determining the factor f, the cross-section of the bearing ring and the ring thickness of the bearing locating housing are taken into consideration, ➤ Figure and ➤ Figure.

Housing ring thickness
DA = diameter of housing bore · DG = outside diameter of housing
Factor f for expansion of the housing
f = factor for expansion of housing · DA = diameter of housing bore · DG = outside diameter of housing · c = factor for cross-section of outer ring

Calculation example for internal clearance

The internal clearance of a radial spherical plain bearing in the fitted condition is calculated using the influence of the interference fit, see link.

Given data

Radial spherical plain bearing GE50-DO with steel/steel sliding contact surface:

    Fit between locating bore and shaft

    M7/m6

    Outside diameter of housing

    ⌀

    120 mm

    Solid steel shaft

    ⌀

     50

    Locating bore

    ⌀

     75

    Radial internal clearance Group N

     60 μm to 120 μm

Required
  • Radial internal clearance in fitted condition.
Assumption
  • Production to centre of tolerance.
Expansion of the inner ring

Expansion of the inner ring, measured on the sphere diameter:

    a

    =

    ÜI  ·  b  ·  0,9

    ÜI

    =

    0,023 mm

    see table

    b

    =

    0,79

    see table

    a

    =

    0,023 mm  ·  0,79  ·  0,9

    a

    =

    0,016 mm.

Contraction of the outer ring

Contraction of the outer ring, measured on the raceway diameter:

    e

    =

    ÜA  ·  f  ·  0,9

    ÜA

    =

    0,009 mm

    see table

    c

    =

    0,85

    see table

    f

    =

    ➤ Figure

    e

    =

    0,009 mm  ·  0,72  ·  0,9

    e

    =

    0,006 mm.

Reduction in radial internal clearance

The reduction in the radial internal clearance is calculated by adding a and e:

    ΔC

    =

    a + e

    =

    0,016 mm + 0,006 mm

    =

    0,022 mm.

Maximum restriction of internal clearance

Maximum possible restriction of radial internal clearance with production to acceptable values:

    Solid steel shaft

    ⌀ 50,025 mm
    (maximum diameter ⌀ 50m6)

    Bearing bore

    ⌀ 49,988 mm
    (minimum diameter according to DIN 620)

    ÜI max

    = 0,037 mm

    amax

    = ÜI max  ·  b  ·  0,9 = 0,037 mm  ·  0,79  ·  0,9

    amax

    = 0,026 mm.

     

    Locating bore

    ⌀ 74,97 mm
    (minimum diameter ⌀ 75M7)

    Bearing outside diameter

    ⌀ 75 mm
    (maximum diameter according to DIN 620)

    ÜA max

    = 0,03 mm

    emax

    = ÜA max  ·  f  ·  0,9 = 0,03 mm  ·  0,72  ·  0,9

    emax

    = 0,019 mm

Maximum reduction in internal clearance

Maximum reduction in the internal clearance in the fitted condition:

  • ΔCmax = amax + emax = 0,026 + 0,019 = 0,045 mm.

The radial internal clearance in the unfitted condition is 0,06 mm to 0,12 mm. The smallest possible initial clearance is 0,06 mm:

  • minimum internal clearance = 0,060 mm – 0,045 mm = 0,015 mm.

The internal clearance in the fitted condition in the least favourable case is 0,015 mm.

Theoretical bearing clearance of metal/polymer composite plain bushes

Bushes with the sliding layer E40 and E50 are pressed into the housing. This provides axial and radial location. No additional means of location are required.

If the recommended mounting tolerances are used with rigid housings and shafts, this gives an interference fit or bearing clearance.

ACHTUNG

Expansion of the housing bore is not taken into account in calcu­lation of the bearing clearance.

Calculation of the interference U is carried out using the tolerances of the housing bore and the deviations for the bush outside diameter Do.

Calculation of bearing clearance

The theoretical bearing clearance is calculated as follows:
Δsmax mm

Maximum bearing clearance, ➤ Figure

Δsmin mm

Minimum bearing clearance, ➤ Figure

dG max mm

Maximum diameter of housing bore

dG min mm

Minimum diameter of housing bore

dW max mm

Maximum shaft diameter

dW min mm

Minimum shaft diameter

s3 max mm

Maximum wall thickness

s3 min mm

Maximum wall thickness.

Theoretical bearing clearance
Do = outside diameter of bush · Di = inside diameter of bush · dW = shaft diameter · dG = diameter of housing bore · s3 = wall thickness of bush · Δs = bearing clearance

Theoretical bearing clearance
after pressing in

The theoretical bearing clearance after pressing in of bushes or flanged bushes of metric sizes or inch sizes is calculated without considering any possible expansion of the bore, see tables.

The theoretical bearing clearance is calculated taking account of the recommended mounting tolerances.

Theoretical bearing clearance
for metric sizes

Diameter of bush

Bearing clearance Δs

E40, E40-B

E50

Di

Do

Δsmin

Δsmax

Δsmin

Δsmax

 mm

 mm

 mm

 mm

 mm

 mm

3

4,5

0,000

0,054

‒

‒

4

5,5

0,000

0,056

‒

‒

5

7

0,000

0,077

‒

‒

6

8

0,000

0,077

‒

‒

7

9

0,003

0,083

‒

‒

8

10

0,003

0,083

0,040

0,127

10

12

0,003

0,086

0,040

0,130

12

14

0,006

0,092

0,040

0,135

13

15

0,006

0,092

0,040

0,135

14

16

0,006

0,092

0,040

0,135

15

17

0,006

0,092

0,040

0,135

16

18

0,006

0,092

0,040

0,135

18

20

0,006

0,095

0,040

0,138

20

23

0,010

0,112

0,050

0,164

22

25

0,010

0,112

0,050

0,164

24

27

0,010

0,112

0,050

0,164

25

28

0,010

0,112

0,050

0,164

28

32

0,010

0,126

0,060

0,188

30

34

0,010

0,126

0,060

0,188

32

36

0,015

0,135

0,060

0,194

35

39

0,015

0,135

0,060

0,194

40

44

0,015

0,135

0,060

0,194

45

50

0,015

0,155

0,080

0,234

50

55

0,015

0,160

0,080

0,239

Theoretical bearing clearance
for metric sizes

Diameter of bush

Bearing clearance Δs

E40, E40-B

E50

Di

Do

Δsmin

Δsmax

Δsmin

Δsmax

 mm

 mm

 mm

 mm

 mm

 mm

55

60

0,020

0,170

0,080

0,246

60

65

0,020

0,170

0,080

0,246

65

70

0,020

0,170

0,080

0,246

70

75

0,020

0,170

0,080

0,246

75

80

0,020

0,170

0,080

0,246

80

85

0,020

0,201

0,080

0,251

85

90

0,020

0,209

0,080

0,251

90

95

0,020

0,209

0,080

0,259

95

100

0,020

0,209

0,080

0,259

100

105

0,020

0,209

0,080

0,259

105

110

0,020

0,209

‒

‒

110

115

0,020

0,209

‒

‒

115

120

0,020

0,209

‒

‒

120

125

0,070

0,264

‒

‒

125

130

0,070

0,273

‒

‒

130

135

0,070

0,273

‒

‒

135

140

0,070

0,273

‒

‒

140

145

0,070

0,273

‒

‒

150

155

0,070

0,273

‒

‒

160

165

0,070

0,273

‒

‒

180

185

0,070

0,279

‒

‒

200

205

0,070

0,288

‒

‒

220

225

0,070

0,288

‒

‒

250

255

0,070

0,294

‒

‒

300

305

0,070

0,303

‒

‒

Theoretical bearing clearance
for inch sizes

Designation

Nominal diameter

Recommended diameter of

Shaft

Housing bore

inch

inch/mm

inch/mm

dW min

dW max

dG min

dG max

EGBZ03

3/16

0,1858

0,1865

0,2497

0,2503

4,719

4,737

6,342

6,358

EGBZ04

1/4

0,2481

0,2490

0,3122

0,3128

6,302

6,325

7,930

7,945

EGBZ05

5/16

0,3106

0,3115

0,3747

0,3753

7,889

7,912

9,517

9,533

EGBZ06

3/8

0,3731

0,3740

0,4684

0,4691

9,477

9,500

11,897

11,915

EGBZ07

7/16

0,4355

0,4365

0,5309

0,5316

11,062

11,087

13,485

13,503

EGBZ08

1/2

0,4980

0,4990

0,5934

0,5941

12,649

12,675

15,072

15,090

EGBZ09

9/16

0,5605

0,5615

0,6559

0,6566

14,237

14,262

16,660

16,678

EGBZ10

5/8

0,6230

0,6240

0,7184

0,7192

15,824

15,850

18,247

18,268

EGBZ11

11/16

0,6855

0,6865

0,7809

0,7817

17,412

17,437

19,835

19,855

EGBZ12

3/4

0,7479

0,7491

0,8747

0,8755

18,997

19,027

22,217

22,238

EGBZ14

7/8

0,8729

0,8741

0,9997

1,0005

22,172

22,202

25,392

25,413

EGBZ16

1

0,9979

0,9991

1,1246

1,1256

25,347

25,377

28,565

28,590

EGBZ18

1 1/8

1,1226

1,1238

1,2808

1,2818

28,514

28,545

32,532

32,558

EGBZ20

1 1/4

1,2472

1,2488

1,4058

1,4068

31,679

31,720

35,707

35,733

EGBZ22

1 3/8

1,3722

1,3738

1,5308

1,5318

34,854

34,895

38,882

38,908

EGBZ24

1 1/2

1,4972

1,4988

1,6558

1,6568

38,029

38,070

42,057

42,083

EGBZ26

1 5/8

1,6222

1,6238

1,7808

1,7818

41,204

41,245

45,232

45,258

EGBZ28

1 3/4

1,7471

1,7487

1,9371

1,9381

44,376

44,417

49,202

49,228

EGBZ32

2

1,9969

1,9987

2,1871

2,1883

50,721

50,767

55,552

55,583

Theoretical bearing clearance
for inch sizes

Designation

Nominal diameter

Inside diameter
after pressing in

Bearing clearance

inch/mm

inch/mm

Di

Do

min.

max.

Δsmin

Δsmax

EGBZ03

0,1875

0,2500

0,1867

0,1893

0,0002

0,0035

4,763

6,350

4,742

4,808

0,005

0,089

EGBZ04

0,2500

0,3125

0,2492

0,2518

0,0002

0,0037

6,350

7,938

6,330

6,396

0,005

0,094

EGBZ05

0,3125

0,3750

0,3117

0,3143

0,0002

0,0037

7,938

9,525

7,917

7,983

0,005

0,094

EGBZ06

0,3750

0,4688

0,3742

0,3769

0,0002

0,0038

9,525

11,906

9,505

9,573

0,005

0,096

EGBZ07

0,4375

0,5313

0,4367

0,4394

0,0002

0,0039

11,113

13,494

11,092

11,161

0,005

0,099

EGBZ08

0,5000

0,5938

0,4992

0,5019

0,0002

0,0039

12,700

15,082

12,680

12,748

0,005

0,099

EGBZ09

0,5625

0,6563

0,5617

0,5644

0,0002

0,0039

14,288

16,669

14,267

14,336

0,005

0,099

EGBZ10

0,6250

0,7188

0,6242

0,6270

0,0002

0,0040

15,875

18,258

15,855

15,926

0,005

0,102

EGBZ11

0,6875

0,7813

0,6867

0,6895

0,0002

0,0040

17,463

19,844

17,442

17,513

0,005

0,101

EGBZ12

0,7500

0,8750

0,7493

0,7525

0,0002

0,0046

19,050

22,225

19,032

19,114

0,005

0,116

EGBZ14

0,8750

1,0000

0,8743

0,8775

0,0002

0,0046

22,225

25,400

22,207

22,289

0,005

0,116

EGBZ16

1,0000

1,1250

0,9992

1,0026

0,0001

0,0047

25,400

28,575

25,380

25,466

0,003

0,119

EGBZ18

1,1250

1,2813

1,1240

1,1278

0,0002

0,0052

28,575

32,544

28,550

28,646

0,005

0,132

EGBZ20

1,2500

1,4063

1,2490

1,2528

0,0002

0,0056

31,750

35,719

31,725

31,821

0,005

0,142

EGBZ22

1,3750

1,5313

1,3740

1,3778

0,0002

0,0056

34,925

38,894

34,900

34,996

0,005

0,142

EGBZ24

1,5000

1,6563

1,4990

1,5028

0,0002

0,0056

38,100

42,069

38,075

38,171

0,005

0,142

EGBZ26

1,6250

1,7813

1,6240

1,6278

0,0002

0,0056

41,275

45,244

41,250

41,346

0,005

0,142

EGBZ28

1,7500

1,9375

1,7489

1,7535

0,0002

0,0064

44,450

49,213

44,422

44,539

0,005

0,163

EGBZ32

2,0000

2,1875

1,9989

2,0037

0,0002

0,0068

50,800

55,563

50,772

50,894

0,005

0,173

Interference fit and bearing clearance of metal/polymer composite plain bushes

The table shows measures that can be taken to influence the bearing clearance and interference fit:

  • at high ambient temperatures
  • depending on housing material
  • depending on housing wall thickness.

Reduced clearance tolerances require tighter tolerances for the shaft and the bore.

Consequences and measures due to environmental influences

Consequences and measures for interference fit and bearing clearance in the case of high ambient temperatures, special housing materials or special wall thicknesses, see table.

Environmental influence

Design and environmental influences

Consequences

Measures

Bearing clearance

Poor interference fit

Change in diameter

Too large

Too small

dG

dW

Notes

Light metal or thin-walled housings

■

‒

‒

●

‒

The housing is more highly stressed;
the permissible stress on the housing must not be exceeded.

Steel or cast iron housings**

‒

■

‒

‒

▼

‒

Bronze or copper alloy housings**

‒

‒

■

▲

▲

Reduce dG and dW by the same
value so that the bearing clearance
is maintained.

Aluminium alloy housings**

‒

‒

■

❍

❍

Reduce dG and dW by the same
value so that the bearing clearance
is maintained.

At temperatures below 0 °C,
the housing is more highly stressed;
the permissible stress on the housing must not be exceeded.

Bushes with thicker anti-corrosion layer

‒

■

‒

❑

‒

The bush and housing will be more highly stressed if appropriate
measures are not taken.

■

Applicable

●

Reduce

❍

Reduce by 0,1% per 100 °C above room temperature

▲

Reduce by 0,05% per 100 °C above room temperature

❑

Increase by 0,03 mm if, for example, the layer thickness = 0,015 mm

▼

Reduce by 0,008 mm per 100 °C above room temperature.

**At high ambient temperatures.

Theoretical bearing clearance of ELGOTEX filament wound bushes

The bushes are pressed as standard into a housing with the tolerance H7. This provides radial and axial location. Due to the contraction of the inside diameter, there is a change in the tolerance of the inside diameter of the bush after pressing in, see table.

ACHTUNG

Expansion of the housing bore is not taken into consideration in calculation of the bearing clearance.

Depending on the selected shaft fit, there is a theoretical bearing clearance, see ➤ equtions:
Δsmax mm

Maximum bearing clearance

Δsmin mm

Minimum bearing clearance

Di max mm

Maximum inside diameter of bush after pressing in, see table

Di min mm

Minimum inside diameter of bush after pressing in, see table

dW min mm

Minimum shaft diameter

dW max mm

Maximum shaft diameter.

Theoretical bearing clearance after pressing-in

For a housing tolerance H7 and the recommended shaft tolerance h7, the minimum and maximum theoretical clearances for the standard dimensions are stated, see table. The data do not take account of any possible expansion of the housing bore.

Theoretical bearing clearance for metric sizes

Diameter
of bush

Inside diameter
after pressing-in

Bearing clearance
for tolerance H7/h7

Di

Do

Di min

Di max

Δsmin

Δsmax

 mm

 mm

 mm

 mm

 mm

 mm

20

24

20,042

20,18

0,042

0,201

25

30

25,042

25,18

0,042

0,201

28

34

28,028

28,176

0,028

0,197

30

36

30,028

30,176

0,028

0,197

35

41

35,038

35,202

0,038

0,227

40

48

40,038

40,202

0,038

0,227

45

53

45,031

45,207

0,031

0,232

50

58

50,031

50,207

0,031

0,232

55

63

55,041

55,237

0,041

0,267

60

70

60,035

60,231

0,035

0,261

65

75

65,035

65,231

0,035

0,261

70

80

70,045

70,241

0,045

0,271

75

85

75,025

75,234

0,025

0,264

80

90

80,025

80,234

0,025

0,264

85

95

85,045

85,274

0,045

0,309

90

105

90,037

90,266

0,037

0,301

95

110

95,037

95,266

0,037

0,301

100

115

100,037

100,266

0,037

0,301

105

120

105,047

105,276

0,047

0,311

110

125

110,025

110,268

0,025

0,303

120

135

120,025

120,268

0,025

0,303

130

145

130,037

130,3

0,037

0,34

140

155

140,037

140,3

0,037

0,34

150

165

150,039

150,302

0,039

0,342

160

180

160,039

160,302

0,039

0,342

170

190

170,036

170,314

0,036

0,354

180

200

180,036

180,314

0,036

0,354

190

210

190,038

190,341

0,038

0,387

200

220

200,038

200,341

0,038

0,387

Operating clearance of ELGOGLIDE plain bushes

Due to the self-lubricating PTFE fabric, maintenance-free ELGOGLIDE plain bushes do not require a minimum radial clearance determined by lubrication conditions.

Fitting without clearance has particular advantages, especially with alternating load directions. Load distribution is also improved, especially during running-in, due to the larger load-bearing areas.

In order to achieve the largest possible load-bearing angle, the operating clearance s must not exceed defined limits. The clearance can be expressed as a function of the relative bearing clearance ψ, see ➤ equation and ➤ Figure.

The guide values for the relative bearing clearance are valid for shaft diameters d = 30 mm to 200 mm, see table.

The ranges for the operating clearance are achievable with the standard tolerances of the plain bushes and where the housing bore and shaft are manufactured to the central tolerance.

Guide values for relative bearing clearance in fitted condition

Shaft diameter

d

Relative bearing clearance

ψ

mm

‰

<

80

≦ 1

≧

80

– 120

≦ 0,75

>

120

– 200

≦ 0,5

Calculation of the operating clearance

s μm

Operating clearance, ➤ Figure

ψ‰

Relative bearing clearance in fitted condition, see table

d mm

Shaft diameter, bore diameter of inner ring.

Operating clearance
s = operating clearance

© Schaeffler Austria GmbH