Double-row tapered roller bearing inclination angle adjustment
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Solution Overview
Problem
Existing double-row tapered-roller bearing units face challenges in maintaining proper inclination angles of inner-ring raceways after assembly, which affects the durability and contact state between rollers and raceways, leading to potential improper contact and reduced durability.
Innovation Solution
The solution involves adjusting the inclination angles of the first and second inner-ring raceways before press-fitting them onto the shaft member, considering the changes in inclination angles due to press-fitting and crimping, ensuring that the angles remain within proper ranges and are essentially equal, using a method that includes adjusting press-fit interferences and providing a spacer to maintain equivalent properties of the inner rings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the inner rings are press-fitted onto the shaft member, then the inner rings are securely fixed to the shaft member, but the inclination angles of the inner-ring raceways change and may fall outside proper ranges
Solution Approach 1:
The patent applies preliminary action by adjusting the inclination angles of the inner-ring raceways before press-fitting the inner rings onto the shaft member. The adjustment is calculated based on expected deformation from press-fitting and crimping, so that after these operations the inclination angles fall within proper ranges. This pre-adjustment compensates for subsequent dimensional changes during assembly.
Solution Approach 2:
The patent applies preliminary anti-action by intentionally setting the inclination angles at values that will counteract the expected increase caused by press-fitting and crimping. By adjusting the angles to be slightly lower before assembly, the deformation during pressing and crimping brings the angles into the optimal range, preventing improper contact between rollers and raceways.
2Strength
If the crimped section is formed to secure the inner rings, then the inner rings are firmly fixed to the shaft member, but the inclination angle of the first inner-ring raceway increases and may exceed proper ranges
Solution Approach 1:
The patent applies preliminary action by calculating and adjusting the inclination angle of the first inner-ring raceway before forming the crimped section. The adjustment amount is determined based on the expected increase in inclination angle due to crimping, ensuring that after crimping the angle falls within the proper range for optimal roller-raceway contact.
3Reliability
If the inclination angles are adjusted to be essentially equal, then the contact state between rollers and raceways is optimized, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies parameter changes by adjusting the inclination angles of the inner-ring raceways to be essentially equal (within ±5 degrees of each other). This parameter optimization ensures proper contact between the tapered rollers and the raceways, improving bearing performance and durability while maintaining a manageable manufacturing process through calculated pre-adjustment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures that the inclination angles of the inner-ring raceways are brought within optimal ranges, improving the durability and contact state of the bearing unit by precisely managing the changes in angle due to assembly processes.
Implementation Method 1
The first inner ring and the second inner ring are press-fitted onto the shaft member
Implementation Method 2
the first inner ring and the second inner ring are connected and fastened to the shaft member by securing the large-diameter-side end surface of the first inner ring by a crimped section formed by plastically deforming one end section in the axial direction of the shaft member
Data Source
Figure 1
Figure 2
Figure 3(A)~3(F)
AI summary
Construction of a double-row tapered-roller bearing unit that is able to improve the contact state between the rolling contact surfaces of plural tapered rollers and a first inner-ring raceway (7) and second inner-ring raceway (8), and a method of manufacturing the same are provided. The inclination angle θ1 of the first inner-ring raceway (7) and the inclination angle θ2 of the second inner-ring raceway (8) in a state before the first inner ring (10) and the second inner ring (11) are press-fitted onto the fitting surface section (13a) of the hub main body (12a), the amount of decrease δθa in the inclination angle of the first inner-ring raceway (7) and the amount of decrease δθb in the inclination angle of the second inner-ring raceway (8) occurring due to press-fitting of the first inner ring (10) and the second inner ring (11) onto the fitting-surface section (13a), and the amount of increase δθk in the inclination angle of the first inner-ring raceway (7) occurring due to formation of the crimped section (15) are adjusted, so that the inclination angle φ1 of the first inner-ring raceway (7) and the inclination angle Θ2 of the second inner-ring raceway (8) in a state after the crimped section (15) has been formed are kept within respective proper ranges.