Rolling Bearing Wedge Preload for Fixed-Position Stability
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Solution Overview
Problem
Existing rolling bearing preloading methods face challenges in maintaining appropriate fixed position preload without increasing the size of the bearing mechanism or impairing maintainability, particularly due to issues like excessive preload, loss of preload, and structural complexity under thermal expansion and load changes.
Innovation Solution
A method and device utilizing a wedge member with a gradually increasing radial thickness, inserted between the outer ring and housing or inner ring and rotating shaft, to apply a fixed position preload through a tightening mechanism, providing direct and firm fixation without the need for additional structural modifications or complex hydraulic systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fixed position preloading is used to obtain higher rigidity, then bearing rigidity is improved, but the amount of preload changes due to thermal expansion of the rotating shaft and housing
Solution Approach 1:
The invention changes the physical state of the preload application by transitioning from a rigid fixed position preload to a controlled elastic deformation preload. The preload amount is adjusted by controlling the degree of elastic deformation of the rotating shaft, which can be modified by changing temperature, material properties, or shaft dimensions, thereby maintaining stable preload under thermal expansion conditions
Solution Approach 2:
The invention makes the preload system dynamic by allowing the preload amount to be adjusted based on operating conditions. The elastic deformation of the rotating shaft provides a mechanism for the preload to adapt to thermal expansion and contraction, transforming the static fixed position preload into a dynamic system that maintains optimal preload stability
2Reliability
If a preload adjustment ring with different coefficient of thermal expansion is added to cancel preload change, then preload stability is improved, but the number of parts increases and structure becomes complicated
Solution Approach 1:
The invention extracts the preload adjustment function from the bearing assembly structure itself and transfers it to the rotating shaft through controlled elastic deformation. This eliminates the need for additional components like preload adjustment rings, as the shaft's inherent elasticity provides the necessary preload stability without increasing structural complexity
Solution Approach 2:
The rotating shaft is given a dual function: it serves both as the rotational support element and as the preload adjustment mechanism. By utilizing the shaft's elastic deformation properties, the same component performs both mechanical support and preload stabilization, eliminating the need for separate adjustment components
3Strength
If a hydraulic mechanism is used to preload the rolling bearing, then rigidity control is improved, but the mechanism size increases and structure becomes complicated
Solution Approach 1:
The invention makes the rotating shaft self-adjusting by utilizing its own elastic deformation properties to maintain optimal preload. The shaft automatically adjusts the preload amount in response to thermal expansion and operational loads without requiring external hydraulic mechanisms, thereby achieving rigidity control through the component itself rather than through complex external systems
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 allows for the application of an appropriate fixed position preload, enhancing the rigidity and maintainability of rolling bearings while preventing displacement and creep, and allowing for easy adjustment of preload without increasing the bearing mechanism's size or complexity.
Implementation Method 1
a first pushing member that pushes the wedge member in the insertion direction of the wedge member and a tightening mechanism that applies a preload to the rolling bearing by elastically deforming the rotating shaft or housing in accordance with a coefficient of elastic expansion
Implementation Method 2
the amount of preload can be changed by the influence of a dimensional change of the rotating shaft 101 and the housing 103 due to thermal expansion
Data Source
AI summary
In a housing that supports a rotating shaft via a rolling bearing which is subjected to predetermined position precompression, a wedge member, the radial thickness of which increases from the leading end towards the base end thereof, is inserted between the housing and the outer circumferential surface of the outer race of the rolling bearing and between the rotating shaft and the inner circumferential surface of an inner race of the rolling bearing, the wedge member being inserted from the leading end thereof along the radial direction of the rotating shaft. The wedge member is fixed by being fastened, ahead in the insertion direction, by bolts and nuts, so that precompression force along with predetermined position precompression is imparted to the rolling bearing.