Double-Row Tapered Roller Bearing for High-Speed Table Accuracy
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Solution Overview
Problem
Machine-tool tables require bearings that can support radial, axial, and moment loads while maintaining high running accuracy and stiffness, especially at high rotational speeds, but existing bearings face issues with increased friction and heating that affect accuracy and productivity.
Innovation Solution
A high-precision tapered roller bearing with a double row configuration, featuring an angle between the bearing and tapered rotational axes greater than 45°, a one-part outer ring with a guide flange for improved lubrication and cooling, and straight or slightly crowned raceways and rollers to enhance tilt rigidity and reduce friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the angle between the bearing rotational axis and the tapered rotational axis is increased to improve tilt rigidity, then tilt rigidity and running accuracy are improved, but radial rigidity decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the angle between the bearing rotational axis and the tapered rotational axis to a specific range (greater than 45°, preferably 50°-65°, most preferably 50°-55°). This parameter optimization resolves the contradiction by finding the optimal balance point where tilt rigidity and running accuracy are sufficiently improved while radial rigidity remains acceptable for the application.
2Productivity
If rotational speed is increased to improve productivity, then productivity is improved, but friction and heating increase which negatively affect accuracy
Solution Approach 1:
The patent applies parameter changes by optimizing the contact angle parameter to reduce friction at high speeds. The specific angle range (50°-55°) is selected to minimize power loss and heating effects while maintaining the required tilt rigidity, thereby enabling high-speed operation (NDm > 200,000) without compromising running accuracy.
Solution Approach 2:
The patent converts the potentially harmful effect of high-speed operation into a benefit by carefully selecting the contact angle that actually reduces friction and heating. The optimized angle transforms what would normally be high-friction high-speed operation into a low-friction regime, turning the harm of increased speed into improved performance and accuracy.
3Strength
If the angle between bearing rotational axis and tapered rotational axis is increased, then tilt rigidity is improved, but friction increases which negatively affects performance
Solution Approach 1:
The patent applies parameter changes by optimizing the contact angle to a specific range that balances tilt rigidity and friction. The angle of 50°-55° is identified as the optimal parameter setting that provides sufficient tilt rigidity for high-precision applications while minimizing friction and power loss at high rotational speeds.
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
The solution increases tilt rigidity and accuracy, reduces friction and heating, and allows for high-speed operation without compromising radial and axial rigidity, thereby improving the performance and precision of machine-tool tables.
Implementation Method 1
at least one set of tapered rollers that are disposed between the inner ring and the outer ring and that roll on the at least one inner raceway and the at least one outer raceway about a tapered-roller rotational axis
Implementation Method 2
a guide flange for the guiding of the tapered rollers can be disposed on the outer ring, wherein the guide flange is formed one-piece with the outer ring
Implementation Method 3
The providing of the guide flange on a fixed outer ring has the advantage that the guide flange can be more easily lubricated and cooled since the fixed outer ring is more easily accessible
Data Source
AI summary
A tapered roller bearing having a diameter of less than 1.5 m includes an inner ring having at least one inner raceway, an outer ring having at least one outer raceway and at least one set of tapered rollers between the inner ring and the outer ring that are configured to roll on the at least one inner raceway and on the at least one outer raceway about a tapered-roller rotational axis while the tapered roller bearing is configured to rotate about a bearing rotational axis. An angle formed by the bearing rotational axis and the tapered-roller rotational axis is greater than 450 and is preferably between 500 and 55°.