Can 60 series deep groove ball bearings withstand axial loads

I. Structural Characteristics and Load-Carrying Characteristics of Deep Groove Ball Bearings

The 60 series deep groove ball bearing is one of the most widely used types of rolling bearings, featuring a simple structure, low friction, high speed, and low noise. Its main structure consists of an inner ring, outer ring, balls, and a cage. Its deep groove design allows it to withstand both radial loads and certain axial loads. Compared to other bearing types, the radius of curvature of the groove in the 60 series bearings is closer to the ball radius, resulting in an extremely small contact angle. Under load, the rolling elements form stable rolling contact with the groove, resulting in a limited axial load capacity.

II. Sources and Effects of Axial Loads

Axial load refers to a force applied along the bearing axis and is commonly found in equipment such as motors, pumps, reducers, and fans. Deep groove ball bearings are subject to axial forces when mechanical systems experience assembly deviations, require axial positioning, or experience thrust from the transmission system. Axial loads can cause the contact point between the ball and the groove to shift, generating additional contact stresses that significantly affect lubricant film thickness, contact fatigue, and temperature rise. For 60 series deep groove ball bearings, correctly assessing the magnitude and direction of axial loads is crucial to ensuring life and reliability.

III. Analysis of the Axial Load Capacity of 60 Series Deep Groove Ball Bearings

Unidirectional Axial Load Capacity: When a deep groove ball bearing is subjected to a unidirectional axial load only, the contact point between the ball and the groove will shift to one side, forming a certain contact angle. Due to the deeper grooves and smaller contact angles, 60 series bearings can typically withstand unidirectional axial loads up to 25% of the radial load. In actual use, if the axial force exceeds the design range, it can easily cause ball slippage, lubricant film rupture, and groove fatigue.

Bidirectional Axial Load Capacity: When the bearing is installed with both inner and outer rings fixed, 60 series bearings can simultaneously withstand bidirectional axial loads. When bidirectional loads are applied, the ball is subjected to loads alternately in the grooves on both sides, but the load capacity is still far lower than the radial load capacity. It is generally recommended that two bearings be mounted back-to-back or face-to-face to share the thrust when bidirectional loads are present.

Impact of load angle and groove design: The groove depth and curvature radius determine the contact angle. The contact angle of 60 series bearings is typically between 0° and 8°, which means limited axial load capacity. To increase load capacity, angular contact ball bearings with larger contact angles (such as the 7000 series) can be selected, typically with contact angles of 15°, 25°, or 40°.

IV. Performance Changes Under Axial Load

Increased Friction and Temperature Rise: Axial forces cause additional sliding of the rolling elements within the grooves, increasing friction and causing elevated temperatures. Excessive temperature rise can cause grease degradation and internal clearance changes, thus shortening bearing life.

Stress Concentration in the Raceways: Axial loads cause the balls to deviate from their center position, resulting in uneven contact stress distribution and a high risk of localized fatigue spalling.

Changes in Internal and External Ring Clearance: When subjected to axial loads, internal clearance decreases, affecting the bearing's rotational flexibility. To prevent excessive preload, an appropriate internal clearance grade (such as C3) is typically selected.

Axial Positioning Stability: In some motor or spindle systems, appropriate axial preload can enhance system rigidity and positioning accuracy. However, excessive axial force can cause permanent deformation of the rolling elements and disrupt contact geometry.

V. Factors Affecting Axial Load-Carrying Performance

Fit and Installation: Overtightening the shaft and housing during bearing installation can cause deformation of the inner or outer ring, altering the groove shape and reducing axial load capacity.

Lubrication Conditions: Under axial load, the lubricating film is easily squeezed and thinned, requiring the use of high-performance grease to maintain film stability.

Operating Temperature and Material Stability: Increased temperature reduces material strength and dimensional accuracy, affecting load-carrying capacity. High-purity bearing steel and a stable heat treatment process can improve fatigue resistance.

Speed ​​Factors: Under high-speed operating conditions, centrifugal force creates additional loads on the balls, exacerbating the effects of axial forces on the contact area. Therefore, high-speed applications require strict control of thrust direction and load magnitude.