Technical requirements for slewing bearings for port cranes

Gear

1 The gear is a standard straight tooth involute gear with a displacement coefficient of +0.5. Other displacement coefficients are allowed as needed.

2 The gear modulus is selected according to the modulus specified in GB1357.

3 slewing bearing gear accuracy and tooth thickness limit deviation according to 11FH in GB10095.

Rolling body

1 The rolling element is made of GCr15 or GCr15SiMn steel. And should comply with the provisions of GB 308 and GB 4661.

2 The rolling element tolerance class shall comply with the requirements of Table 4. And the surface roughness Ra of the steel ball is allowed to be 0.2 μm. The batch length variation VLwL of the cylindrical roller is not required; the roller single length deviation ΔLws and the end face runout SDw are allowed to not exceed twice the specified value.

Support ring

1 The support ring is made of 42CrMo quenched and tempered steel in accordance with GB3077 and allowed to be made of other materials with equivalent properties. The quenching and tempering hardness is HB260~300.

2 For the steel of the slewing ring for offshore cranes according to the test method specified in GB 4159 standard, the average value of the three samples of the shock absorption work at -20 °C should not be lower than 42J, one of which should be Not less than 27J.

3 Surface hardened support ring raceway surface hardness requirements HRC55 ~ 60. The effective hardened layer depth (hardness reaches the surface depth of the raceway above HRC48) D.

4 After the raceway is quenched, a soft belt is allowed. The requirements are as follows:

1. For the non-blocking hole, the width of the soft belt should not exceed 2Dw when Dw≤25 mm; when Dw>25 mm, it should be no more than 50 mm. The width of the flexible band of the support ring with the blocked hole should be no more than the diameter of the blocked hole plus 35 mm.
2. Except for the support ring soft belt with the blocked hole, it should be placed at the blocked raceway without marking. The other support rings should be marked with a permanent “S” mark at the non-installation joint of the soft belt. For the soft belts with double semi-support rings, in addition to the above markings, the semi-support ring soft belts should be coincident when mating and assembling.

Isolation block

The spacer material is made of polyamide 1010 resin conforming to HG2-869.

Seal ring

The sealing ring is made of NBR SN7453B which meets the requirements of GB7040.

Oil hole

The nozzle should be resistant to seawater corrosion.