Manufacture of Rolling Bearings - Forming of Rings

Manufacturing Process of Rolling Bearings– Retainer Forming

Introduction

Rolling bearings are essential components in variety of power transmission and industrial applications. The three main components of rolling bearings are the inner and outer rings, as well as the roller elements. Before the rings, rollers, and cages are assembled, they must first go through several manufacturing processes. This article discusses the process of forming the retainer, which is used to hold the roller elements in place.

Forming the Retainer

The process of forming the retainer begins with a circular piece of sheet metal which is stamped with a series of grooves and holes in order to create the “cups” and “baffles” that make up the retainer. After this is completed, the cup and baffle parts are then formed into a retainer using cold forging or stamping technologies. This process creates the form and shape needed for the retainer without the need for additional machining or heating.

The forming process requires the use of specialized tooling, such as a roll forming die and a post forming die. The roll forming die is used to create the cup and baffle sections of the retainer while the post forming die is used to shape the stamped pieces into an integral part.

Once the cup and baffle pieces have been formed, they are then heat-treated in order to increase the hardness of the material and improve their strength and durability. This heat-treating process also increases the material’s resistance to wear, which is essential for the proper functioning of the retainer.

After heat treatment, the cup and baffle pieces are then assembled into the retainer. The pieces must be aligned and press-fit into the retainer in order for it to function correctly. Once the pieces are aligned and press-fit into the retainer, it is then ready to be installed into the bearing assembly.

Conclusion

Forming the retainer is an essential step in the manufacturing and assembly of rolling bearings. Properly engineered and designed tooling is essential for the proper forming of the retainer, with the correct hardness achieved through proper heat-treatment and press-fitting into the bearing assembly. Following these processes and using the correct tools, the retainer will ensure proper functioning within a bearing assembly.

Collar forming is a necessary process in manufacturing rolling bearings. There are different methods for collar forming of bearing rings, and most of them are divided into three categories: cold forming, warm forming and hot forming.

Cold forming is the most commonly used method. It uses special tools and strictly controlled process parameters to cold deformation the bearing rings and make their outside profiles correctly form the collars of specified shapes and sizes.

The advantage of cold forming is that it can keep the material characteristics of raw materials unchanged, reduces the work hardening of metal materials, saves materials and time, and is not affected by the environmental factors. However its big limitation is that it can only process bearing rings of common sizes.

Warm forming is a kind of high precision bearing collar forming. Generally, the bearing rings are heated to an acceptable temperature first, and then the carbide mould is used to bring the accurate external profile of the bearing collars. Because of its high precision, this kind of forging can correct the size deviation of the bearing collars caused by the cold forming.

The advantage of warm forming is that it can save materials, shorten process flow and obtain high precision of the bearing collars. The disadvantage is that it needs to be heated, and the bearing rings may be deformed during the cooling, while the external shape of bearing collars may not be corrected.

Hot forming is a kind of advanced collar forming process. It is mainly used to form the polygonal bearing collars. The bearing rings are first heated to about 850℃, and then the roller is used to roll the external profile into the bearing collars after cooling. This method can get the accurate bearing collars and prevent it from forming the flashing.

The advantage of this method is that it does not destroy the properties of the bearing material, and it can also obtain the high-precision bearing collars. The disadvantage is that this method can only be used to form the bearing collars with particular shape and size.