What are the main differences between needle bearings and ball bearings?

The core difference between needle roller bearings and ball bearings lies in the shape of the rolling elements and the load-bearing characteristics: needle roller bearings use slender cylindrical rollers, which have stronger radial load capacity and compact structure; ball bearings use spherical rolling elements, which have both radial and axial load capacity and higher speed.

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Differences in rolling element structure and contact mode

① Needle bearing

★ Use cylindrical needle rollers with a diameter of ≤5mm and an aspect ratio of ≥2.5.

★ The rolling element and the track are in line contact, and the contact area is large.

② Ball bearing

★ Use spherical rolling elements to achieve point contact.

★ The contact area is small but evenly distributed.

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‌Load-bearing characteristics comparison

① ‌Radial load capacity‌.

★ Needle roller bearings have stronger radial load capacity at the same size and are suitable for high radial load scenarios.

★ Ball bearings have more spheres, so the load distribution of a single rolling element is more balanced.

② ‌Axial load adaptability‌.

★ Needle roller bearings can only withstand pure radial loads.

★ Ball bearings can withstand radial, axial and combined loads (such as angular contact type).‌‌

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‌Application scenarios and performance parameters‌

① ‌Space adaptability‌.

★ The outer diameter of the needle bearing is minimized, which is suitable for mechanical structures with limited radial installation space (such as gearboxes, motorcycle connecting rods). ‌‌

★ The ball bearing has a compact structure and is suitable for high-speed precision equipment (such as motors and precision instruments). ‌‌

② ‌Speed limit‌.

★ Needle bearings are prone to centrifugal force when running at high speeds due to the large aspect ratio of the needle rollers, and are suitable for lower speeds. ‌‌

★ Ball bearings have low friction resistance and the maximum speed can reach 2-3 times that of needle bearings.