US Synthetic Bearings Site

Thrust Bearings

How do Thrust Bearings Work?

In down-hole drilling tools, large thrust loads can result from drilling and from the hydraulic loading caused by drilling mud flowing through tool components. This results in a large axial load that must be carried when mud is circulating through the tool in the off-bottom position. When the tool is drilling (on-bottom), the weight-on-bit (WOB) is transmitted to the motor drive shaft in a direction opposite to the loads resulting from the circulation of the drilling mud through the power section. Both the on-bottom and the off-bottom loads in mud motors (and other drilling tools) are taken up by thrust bearings.

Why are diamond thrust bearings better than ball bearings?

Conventional thrust bearing designs for down-hole drilling tools often utilize mud-lubricated or sealed ball bearings. US Synthetic PDC bearings provide a high-performance alternative to these conventional bearings. The diamond inserts in our thrust bearings are virtually impervious to abrasive particles in the drilling mud that often cause ball bearings to wear out quickly.

Our thrust bearings deliver:

• LIFE - longer tool life
• LENGTH - compact and robust design
• LOAD - increased load capacity

US Synthetic diamond bearings are also capable of sustaining high loads and speeds. The high load-carrying capacity of US Synthetic bearings can help reduce the overall length of the bearing section of a drilling tool. Because of the limited load-carrying capacity of ball bearings, multiple ball bearing sets (i.e., 8 to 14 sets) are often use to take up the large thrust loads in the tool. Diamond bearings, when used properly, can take-up the same loads with as few as one or two bearings sets.

A PDC thrust bearing set is comprised of a rotating and non-rotating bearing ring. The non-rotating ring is typically attached to the tool housing and the rotating ring is typically attached to the tool drive shaft. The bearing rings are usually made from stainless steel and have an array of PDC inserts equally spaced on a specified diameter.

As with US Synthetic radial bearings, our PDC thrust bearings generate heat during operation. The PDC withstands high temperatures more effectively than conventional metal bearings. This heat must be removed from the bearings in order for them to function properly. In drilling tools, the drilling mud is used as a coolant. In other applications, oil or water may be used as a bearing coolant. Please consult with a US Synthetic Bearings consultant to determine the diamond bearing cooling requirement for your specific application.

For more information on US Synthetic thrust bearings and down hole drilling components, contact us today or read more about our technology advantage.