Description: Rustenburg South Africa is well-known associated minerals, mainly platinum ore, copper and nickel as a byproduct. Rustenburg consists of two famous gold-clad mines: Merensky and UG2 reefs. In recent years, strikes have continued and production has often been affected.

Capacity and output: The current annual production capacity is 27,000 tons, and the annual output is about 26,000 tons (metal amount).

Shareholders: Currently Anglo American Platinum Corporation Ltd is the sole shareholder of the mine, accounting for 100% of the shares.

List of nickel ore production in recent years: metal tons

2006 2007 2008 2009 is expected to be expected in 2010

27000 23400 26555 27000 27000

Angular contact Ball Bearings

 

Angular Contact Ball Bearing has high limit rotational speed, they can carry radial load and axial load simultaneously, they can also withstand purely radial load. The axial load carrying capacity depends on the magnitude of contact angle and increases with increasing contact angle.

Structures

1. Non-separable angular contact ball bearings

This inner ring and outer ring of this type of bearings cannot be separated and comprises following structures:

Contact angle α=15°      counter bore on outer ring,7000Ctype

Contact angle α=25°      counter bore on outer ring,7000ACtype

Contact angle α=40°      counter bore on outer ring, 7000B type

2. Four-point contact ball bearings

This type of bearings is separable bearings. Whereof, QJ0000 type has two-piece inner ring and QJF0000 type has two-piece outer ring. Their contact angles are same as 35°.When received no load or pure radial load, the steel balls of the Ball Bearing contact with the four points of the rings. When it is received a pure axial load, the steel balls perform a two-point contact with the ring. In addition, besides the axial load from both directions, this kind of bearing can take torque-load as well.

3. Double row angular contact ball bearings

This kind of bearings can accommodate radial loads as well as axial loads acting in both directions; they can also take loading moment. They can restrain the axial displacement from both directions of the shaft or housing; the contact angle is 30° (or 40°)

Permissible tilt angle

There is only a little inclination between the inner ring and outer ring of angular contact bearings, the permissible tilt angle varies according to the internal clearance when the bearings are operating, the bearing dimensions, internal design, force and loading moment received by the bearings. The value of the maximum permissible tilt angle should be able to ensure that no much extra stress to be generated inside the bearings.

The tilt angle existing between the inner ring and outer ring will influence the bearing service life. Meanwhile, the running accuracy is decreased down and noise increased.

Tolerance and clearance

The tolerances of general angular contact bearings are class normal P0, class P5 and P6. Class P4 and P2 are applicable to machine tool spindles and bearing amount in pairs.

Clearance of single row angular contact bearing is decided by the contact angle, which is guaranteed by manufacturing.

Axial clearance of Four-point contact ball bearings is listed in table 1.

Cage material

Generally, the cage of angular contact bearing is pressed cage of steel sheet or brass cage, and it is solid brass cage for two row angular contact bearing.

Dynamic equivalent radial load

Single-row angular contact ball bearings with a contact angle of 15°

Single bearing or bearing in pairs(7000 C.7000 C/DT)

Fa/Fr≤e         Pr=Fr 

Fa/Fr>e          Pr=0.44Fr+YFa

Back-to-back and face to face arrangements(7000 C/DB.7000 C/DF)

Fa/Fr≤e         Pr=Fr+Y1Fa       

Fa/Fr>e          Pr=0.72Fr+Y2Fa    

Single-row angler contact ball bearings with a contact angle of 25°

Single bearing or bearing in pairs(7000 AC.7000 AC/DT)

Fa/Fr≤0.68      Pr=Fr             

Fa/Fr>0.68       Pr=0.41Fr+0.87Fa   

Back-to-back and face to face arrangements(7000 AC/DB.7000 AC/DF)

Fa/Fr≤0.68      Pr=Fr+0.92Fa       

Fa/Fr>0.68       Pr=0.67Fr+1.41Fa    

Single-row angular contact ball bearings with a contact angle of 40°

Single bearing or bearing in pairs (7000 B.7000 B/DT)

Fa/Fr≤1.14      Pr=Fr             

Fa/Fr>1.14       Pr=0.35Fr+0.57Fa   

Back-to-back and face to face arrangements(7000 B/DB.7000 B/DF)

Fa/Fr≤1.14      Pr=Fr+0.55Fa      

Fa/Fr>1.14       Pr=0.57Fr+0.93Fa   

Four point contact ball bearings with a contact angle of 35°

Fa/Fr≤0.95      Pr=Fr+0.66Fa      

Fa/Fr>0.95       Pr=0.6Fr+1.07Fa    

Double-row angular contact ball bearings with a contact angle of 45°

Fa/Fr≤1.34      Pr=Fr+0.47Fa      

Fa/Fr>1.34       Pr=0.54Fr+0.81Fa   

Static equivalent radial load

Single-row angular contact ball bearings with a contact angle of 15°

For single bearing or bearing in pairs(7000 C.7000 C/DT)

 

P0r=0.5Fr+0.46Fa   

P0r<Fr  P0r=Fr

For back-to-back and face-to-face arrangements (7000 C/DB.7000 C/DF)

P0r=Fr+0.92Fa

Single-row angular contact ball bearings with contact angle of 25°

For single bearing or bearing in pairs (7000 AC.7000 AC/DT)

P0r=0.5Fr+0.38Fa  

when P0r<Fr  let P0r=Fr

For two bearings in back-to-back and face-to-face arrangements

P0r=Fr+0.76Fa

Single-row angular contact ball bearings with contact angle of 40°

For single bearing or bearing in pairs

P0r=0.5Fr+0.26Fa   

when P0r<Fr  let P0r=Fr

For two bearings in back-to-back and face-to-face arrangements

P0r=Fr+0.52Fa

Four point contact ball bearings

P0r=Fr+0.58Fa

Double-row angular contact ball bearings with contact angle of 45°

P0r=Fr+0.44Fa

Fr  Actual radial load of the bearing.

Fa   Axial load of the bearing

The values of e .Y .Y1 .Y2  see Table 2.

Table 1   Axial internal clearance of four point contact ball bearings

                                        μm

Nominal bore diameter  d

mm

C2 clearance

Standard clearance

C3

clearance

C4

clearance

Over

To

Min

Max

Min

Max

Over

To

Min

Max

10

18

40

 

60

80

100

 

140

180

220

 

260

18

40

60

 

80

100

140

 

180

200

260

 

300

15

26

36

 

46

56

66

 

76

96

115

 

135

55

66

86

 

96

116

136

 

156

176

195

 

215

45

56

76

 

86

96

116

 

136

156

175

 

195

85

106

126

 

136

156

176

 

196

216

235

 

275

75

96

116

 

126

135

156

 

176

196

215

 

255

115

146

166

 

176

196

216

 

236

256

295

 

335

105

136

156

 

166

176

196

 

216

236

275

 

295

145

186

206

 

216

236

256

 

276

296

335

 

355

 

Table 2   Calculate Coefficient

                           Î¼m

e

Y

Y1

Y2

0.172

0.345

0.689

1.03

1.38

2.07

3.45

5.17

6.89

0.38

0.4

0.43

0.46

0.47

0.5

0.55

0.56

0.56

1.47

1.4

1.3

1.23

1.19

1.12

1.02

1

1

1.65

1.57

1.46

1.38

1.34

1.26

1.14

1.12

1.12

2.39

2.28

2.11

2

1.93

1.82

1.66

1.63

1.63

Dw is the diameter of the rolling element

Angular Contact Ball Bearing

Machined Cage Angular Contact Ball Bearing,Pressed Cage Angular Contact Ball Bearing,One Row Angular Contact Ball Bearing,Two Row Angular Contact Ball Bearing

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