Thin-section deep groove ball bearings are crucially developed for applications with space constraints. They primarily handle radial loads but can also manage combined radial and axial loads when increasing radial clearance. Compared to other bearings of the same size, these bearings exhibit lower friction coefficients and higher maximum speeds. However, they are not suitable for heavy loads or impact resistance. Applications include joints or rotating parts in robotics, medical equipment, measuring instruments, radar, cameras, optical devices, and stepper motors.
During manufacturing, bearings undergo various cold and hot processing steps, including forging, machining, and heat treatment.
Forging: For large-sized thin-section bearing rings with a high length-to-diameter ratio, the method involves forging two or more pieces together. After rough grinding, rings are separated using wire cutting to reduce forging complexity, minimize ring deformation and residual machining allowance, save raw materials, and enhance production efficiency.
Machining: Key factors include clamping positioning, excessive cutting forces, inadequate fixture design, thermal deformation during cutting, and vibration affecting machining precision. To reduce stress-induced deformations during machining, rough turning utilizes unfired steel jigs with larger enveloping circular contact areas, such as multi-point chucking (twelve-point or twenty-four-point). Adjustments in positioning clamping methods (from radial clamping to end-face positioning compression), process parameters (high-speed cutting, minimal back cutting, larger primary clearance angle for tools, smaller tool tip arc radius, and appropriate cutting fluid selection) are made. Following rough turning, an additional tempering process is added to relieve stress. Subsequently, soft grinding of end faces and precision machining of rings are conducted.
Heat Treatment: Internal structure of rings undergo phase transformation from austenite to martensite, reducing density and expanding volume, generating structural stress. Additionally, rings quenched from high temperatures (typically 830-845°C) rapidly undergo heat-quenching to cold, generating thermal stress. When these stresses exceed material yield limits, plastic deformation occurs. Controlled deformation via die quenching is typically employed. Rings that exceed process requirements due to excessive outer diameter deformation post-quenching are corrected through comprehensive reshaping followed by tempering to maintain within process specification ranges.
Manufacturing rings and ball materials include 52100 chrome steel, 440C stainless steel, ceramics, etc. Chrome steel is standard due to its high load capacity and low noise characteristics. Thin-section chrome steel bearings feature steel cages and appropriate lubricants, suitable for continuous use at 120°C or intermittent temperatures up to 150°C. Beyond these temperatures, load capacity of chrome steel diminishes. Chrome steel bearings are not corrosion-resistant and unsuitable for corrosive environments. 440C stainless steel and ceramics are corrosion-resistant high-quality materials.
Design 6700 series thin-section bearings employ crown-type cages. 6800 and 6900 series bearings generally use two-piece ribbon cages. Certain bearing sizes utilize high-speed TW nylon crown-type cages. Steel sheet stamping cages are used for diameters less than 400mm, while solid brass cages are preferred for diameters exceeding 400mm. Use of nylon reduces sliding friction between balls and cages. Individual nylon cage torque losses decrease by 30-40%, contributing to an overall bearing torque reduction of 50-65%.
Thin-section deep groove ball bearings can be equipped with metal dust shields, with larger 6700 series bearings fitted only with seals. Most bearings feature rubber contact seals or low-friction non-contact rubber seals. Open thin-section deep groove ball bearings are lubricated with light oil. Dust shields or sealed thin-section bearings typically contain grease. For low-speed, low-friction applications, sealed bearings may use lubricating oil. Specific lubricating oils, greases, or dry lubricants can be specified.
AUBEARING offers standard tolerance grades (ABEC1-ABEC7) and radial clearance ranges (C2\CN\C3\C4\C5).
