Segmented Roller Bearing Cage With Stable Thermal Gap Control
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Solution Overview
Problem
Conventional roller bearings experience unstable rotation and premature failure due to collisions between cage segments caused by an excessively large final gap that shrinks as temperature rises, leading to collision sounds and damage in large-sized bearings like those supporting wind power generators.
Innovation Solution
The roller bearing design features circumferentially arranged cage segments with a defined gap between the first and last segments, using a resin with a thermally expandable filler to maintain a stable gap size within the predetermined temperature range, ensuring minimal expansion and preventing collisions, with the filler's coefficient of linear expansion adjusted to be less than that of the steel rings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the final gap is set to a larger size to prevent cage segment collision at high temperature, then the reliability is improved, but collision sounds and damage occur at low speed rotation due to excessive gap size
Solution Approach 1:
The invention changes the material parameter of the cage segments by using a resin composition with specific physical properties (coefficient of linear expansion between 5×10^-6 and 15×10^-6 /°C) to optimize the gap behavior across the temperature range, preventing both excessive gap closure at high temperature and excessive gap size at low temperature
Solution Approach 2:
The invention utilizes thermal expansion characteristics by selecting a resin material whose linear expansion coefficient matches that of the steel rings, ensuring that the gap between cage segments remains stable across temperature changes and does not cause collision sounds or damage
2Object-generated harmful factors
If the final gap is set to a smaller size to reduce collision sounds at low speed, then the harmful factors are reduced, but the gap completely disappears at high temperature causing cage segment deformation
Solution Approach 1:
The invention optimizes the resin composition parameters (coefficient of linear expansion between 5×10^-6 and 15×10^-6 /°C) to ensure the gap maintains appropriate size across the operating temperature range, preventing both collision sounds and gap disappearance
Solution Approach 2:
The invention applies thermal expansion principles by matching the resin's linear expansion coefficient to that of the steel rings, ensuring stable gap dimensions during temperature variations and preventing cage segment deformation
3Adaptability or versatility
If a resin with high linear expansion coefficient is used to accommodate gap shrinkage, then the adaptability is improved, but the gap shrinks excessively at high temperature causing instability
Solution Approach 1:
The invention optimizes the resin material parameters by selecting a composition with a coefficient of linear expansion between 5×10^-6 and 15×10^-6 /°C, which provides appropriate temperature adaptation while maintaining gap stability
Solution Approach 2:
The invention utilizes controlled thermal expansion by matching the resin's expansion characteristics to the steel rings, ensuring the gap remains stable across the operating temperature range from -40°C to 150°C
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 design prevents collision sounds and damage to cage elements, ensuring stable operation of the roller bearing from the start, particularly in large-sized applications like wind power generators, by maintaining a stable gap size and reducing undesirable movements.
Implementation Method 1
the resin and the filler have, in combination, a coefficient of linear expansion of less than 1.0 × 10 -5... the circumferential dimension of the gap R is, at the upper limit value (150°C) of the predetermined temperature range, less than 0.12% of the circumference
Data Source
Figure 1
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AI summary
A tapered roller bearing is provided which includes an inner ring (1) and an outer ring (2) both made of a steel material; and a plurality of cage segments (5) circumferentially continuously disposed between the inner ring (1) and the outer ring (2), into an annular shape. The cage segments (5) are made of a resin containing a predetermined amount of a predetermined thermally expandable filler, and having, in combination with the filler, a coefficient of linear expansion of less than 1.0 X 10-5/°C. A gap (R) is defined between the flat surfaces of the firstly mounted cage segment (5a) and the lastly mounted cage segment (5b). The amount by which the cage segments (5) thermally expand is limited such that, at the upper limit value of a bearing use temperature range, the gap (R) is less than 0.12% of the circumference of the circle passing through the centers of the annular cage segments in the radial thickness directions of the cage segments (5).