The manufacturing process of single row tapered roller bearings includes multiple links such as raw material preparation, ring and roller processing, heat treatment, precision grinding, assembly and testing. Its core is to ensure that the bearings have high hardness, wear resistance and dimensional accuracy by accurately controlling the parameters of each link. The specific process flow is as follows:
1. Raw material preparation and cutting
Material selection
Commonly used GCr15 bearing steel has a precise ratio of carbon and chromium content to ensure that the bearings have high wear resistance and hardness.
CuttingCut round steel into billets according to size, with a length error controlled within ± 5mm, providing accurate raw materials for subsequent forging.
.II. Ring Forging and Preliminary Forming
Heating
Heat the billet to 1050-1100 ℃ to soften the steel and facilitate plastic deformation.
.Forging
By forging, the blank is forged into the preliminary shape of the bearing ring.
. During the forging process, repeated upsetting and elongation are required to eliminate internal defects in the metal, optimize the microstructure, and improve the density.Leave machining allowance
After forging is completed, a machining allowance of 3-5mm should be reserved for the outer and inner diameters of the ring to provide space for subsequent turning and grinding.
.III. Rough Machining and Initial Size Determination
Outer Circle Turning
Turn the outer diameter size to 1-1.5mm larger than the finished product, and control the cylindricity error within ± 0.05mm.
Inner Hole Turning
Turn the inner hole size to 1-1.5mm smaller than the finished product, and the coaxiality error does not exceed ± 0.03mm.
End Face Turning
Ensure the flatness of the end face, and the surface roughness reaches Ra6.3, providing a stable reference surface for subsequent processing.
.Fourth, Heat Treatment Strengthening Performance
Quenching
Heat the collar to 840-860 ℃ and hold for 30-40 minutes to fully austenitize the internal structure of the steel.
. Subsequently, the oil was rapidly cooled to 60-80 ℃, forming a martensitic structure with a hardness of HRC60-62.Tempering
After quenching, the internal stress of the ring is high and prone to cracking, requiring tempering treatment.
. Heat to 150-180 ℃, hold for 2-3 hours, eliminate internal stress, and adjust the hardness to HRC58-60 to improve toughness.Fifth, Precision Grinding and Dimensional Refinement
Cylindrical Grinding
Ceramic bond grinding wheel is used, with dimensional accuracy controlled within ± 0.002mm and surface roughness reaching Ra0.8.
.Internal hole grinding
Resin bonded grinding wheel is used, with a hole diameter tolerance controlled within ± 0.0015mm and a cylindricity error not exceeding ± 0.001mm.
Cone surface grinding
Special cone grinding machine is used to adjust the grinding wheel angle and worktable tilt angle to ensure that the cone surface angle error is within ± 2 'and the straightness error of the busbar does not exceed ± 0.001mm. During the grinding process, sufficient cooling and lubrication are required to prevent surface burns on the ring.
.VI. Roller Manufacturing and Precision Control
Blank Cutting
Cut the bearing steel bar into blanks of roller length.
.Roughly grind the outer circle
Use a centerless grinder to roughly grind the outer circle, leaving a margin of 0.2-0.3mm.
. Spherical ProcessingBy grinding with a forming grinding wheel, the accuracy of the spherical curvature radius of the roller is ensured to be within ± 0.005mm.
Heat Treatment
The roller needs to undergo quenching and tempering treatment, with parameters similar to those of the ring, but needs to be fine tuned according to the characteristics of the roller.
.Fine grinding of outer circle and spherical surface
The dimensional tolerance of the outer circle is controlled at ± 0.001mm, and the surface roughness reaches Ra0.4;
; The surface roughness of the spherical surface reaches Ra0.2. Size groupingAfter precision grinding, the rollers should be grouped according to their diameters, and the diameter difference of the same group of rollers should not exceed ± 0.0005mm to ensure uniform force distribution during assembly.
.7. Assembly and Final Inspection
Cleaning and greasing
Clean the ring and roller, remove oil and iron filings, and apply a thin layer of lubricating grease on the surface of the raceway.
.Assembly cage
Insert the rollers into the ring raceway according to the quantity and spacing, press them into the cage, and ensure that they are installed in place without tilting or loosening.
.Sealing test
Fill the bearing with a certain pressure of gas and observe whether there are bubbles coming out in kerosene to ensure good sealing.
.Clearance detection
Use a dedicated clearance measuring instrument to check whether the radial clearance is within the specified range (such as 0.01-0.03mm for bearings with an inner diameter of 50mm).
. Anti rust treatmentBearings that pass the inspection are coated with anti rust oil, wrapped in plastic film, and packed in paper boxes for factory delivery.
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