Standard PD two-bearing housings are designed for grease lubrication. Housings for oil lubrication are available on request.
The lubricant should be selected based on the operating conditions of the bearings. For additional information, refer to Lubricant selection
PD housings are supplied with inboard flinger rings made of grey cast iron (fig. 1
). The flinger rings serve to retain grease at the bearing position and to prevent over-lubrication. The excess grease is collected in the large space in the middle of the housing.
Initial grease fill
If no other requirements exist, the free space in the bearings should be completely filled with grease and the free space between the cover and flinger ring should be filled to 100%.
Initial grease fill for PD units
PD units are greased at the factory with SKF LGMT 2, a high-quality mineral oil based grease with a lithium thickener and good rust inhibiting properties. The operating temperature range of the grease is –30 to +110 °C (–20 to +230 °F).
Relubrication is possible via two G 1/4 or G 1/8 grease fittings (depending on size), one on each end of the housing (fig. 2
). There is minimal risk of over-greasing because excess grease is collected in the large space in the middle of the housing. When applying grease via the grease fittings, the shaft should be rotating.
SKF recommends replenishing the housings with SKF LGMT 2, a high-quality mineral oil based grease with a lithium thickener and good rust inhibiting properties. For vertical shaft arrangements, SKF LGMT 3 grease should be used with half the interval required for a similar horizontal application.
To calculate the relubrication interval and the quantity of grease needed for replenishment, refer to the relevant product information.
Where high speeds preclude the use of grease as a lubricant, large PD housings can be modified for oil bath or circulating oil lubrication systems. The housings are fitted with special oil seals. For additional information, contact the SKF application engineering service.