Thin-walled bearings have the advantages of light mass, compact structure, small moment of inertia, etc. They are widely used in industrial robots, aerospace vehicles, space satellites, medical and other industrial fields, and the market size is gradually increasing. But the thin wall bearing cross-sectional area is small, so that its radial wall thickness is very small, poor rigidity, very easy to produce large radial deformation, therefore, the collar in the turning process, heat treatment, grinding process and many other processes, in order to prevent the collar roundness, flatness super poor, oval, prismatic and end warpage deformation and other defects, need to use special means of bearing collar for protective processing

Thin-walled bearings, as the name implies, have a small wall thickness. In engineering practice, the ratio of the diameter of the part to the wall thickness is greater than 15 parts, called thin-walled parts. The bearing industry usually uses the inner and outer ring wall thickness coefficient K (outer ring outer diameter size and outer groove diameter size ratio D/De, inner ring inner groove diameter size and inner diameter size ratio di / d) to

The processing difficulties of thin-walled bearing rings and measures to solve them -

1、Forging process

For the large size and length-diameter ratio of small thin-walled bearing rings, the use of two or more pieces of forging method of production, rough grinding process and then the use of wire cutting method will be separated from the ring, in order to reduce the forging process processing difficulties, reduce the deformation of the ring and end machining allowance, save raw materials, improve production efficiency.

2、Turning process

In the turning process, mainly clamping positioning, cutting force is too large, the fixture design is not reasonable, cutting heat deformation and vibration in the cutting process affects the machining accuracy. In order to reduce the deformation due to excessive turning stress, the use of larger envelope round contact area and unhardened steel soft jaws clamping ring for rough turning, such as the use of multi-point clamping chuck (twelve-point clamping or twenty-four-point clamping); change the positioning clamping scheme (change the radial clamping for the end positioning pressure mode); adjust the process parameters (high-speed cutting, small back draft, tooling larger main offset angle, smaller tool tip arc radius, reasonable choice of cutting fluid, etc.). After rough turning, an additional tempering is added to eliminate stresses. Afterwards, soft grind the end face and then finish turn the collar.

3、Heat treatment

In the heat treatment process, the internal organization of the ring produces phase changes, mainly from austenite to martensite, density becomes smaller, volume expansion, resulting in tissue stress; in addition, the ring from high temperature (thin-walled products are generally 830 ~ 845 ℃) expansion state rapid quenching and cooling, resulting in thermal stress. When these two internal stresses exceed the yield limit of the material, the material will undergo plastic deformation. Usually use the pressure die quenching control deformation, no conditions for pressure die quenching, and quenching after the outer diameter deformation is too large than the process requirements of the ring, the use of comprehensive shaping and then tempering method to correct, so that it is controlled within the process requirements.

4、Grinding

The main thing in grinding is: to choose the appropriate grinding equipment, processing method and grinding process parameters. For example, adopt the method with reinforced ring, "one dragging two" structure for processing; adopt the method of multiple fine adjustment of the machine tool for grinding the outer diameter surface; increase the tempering stabilization treatment during the process, etc. to ensure that the grinding quality of the collar meets the process requirements.

The above is a simple explanation of the processing difficulties and solutions for thin-walled bearing rings. When using thin-walled bearings, we must pay attention to the problems that exist, and pay attention to conservation in use, so that the bearing can be used to grow in time to save costs.