Mechanical Backup Bearing With Flat Spring Thermal Compensation
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Solution Overview
Problem
Existing bearing systems fail to effectively accommodate thermal expansions and contractions of bearing components, leading to uncontrollable clamping pressure and potential mechanical contact issues when magnetic bearings are not sufficient for support.
Innovation Solution
A mechanical backup bearing system using flat springs to compensate for thermal expansions, with a duplex bearing arrangement and a retainer that maintains preloaded force on the outer race, preventing excessive deflection and ensuring continuous operation without mechanical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical backup bearing is used to support the rotational portion when magnetic bearing support is insufficient, then reliability is improved, but thermal expansion of bearing components causes uncontrollable clamping pressure and potential mechanical contact issues
Solution Approach 1:
The patent applies the dynamics principle by replacing rigid clamping structures with elastic elements (springs) that can dynamically adjust to thermal expansions and contractions of the bearing components. The springs allow the outer race to move axially while maintaining controlled contact pressure, transforming the static clamping system into a dynamic one that adapts to temperature changes during operation.
Solution Approach 2:
The patent utilizes parameter changes by designing the spring system to change its elastic properties based on temperature variations. As the bearing components undergo thermal expansion, the spring's deflection and resulting clamping pressure automatically adjust, maintaining optimal contact conditions without requiring external control mechanisms.
2Manufacturing precision
If the outer race is rigidly clamped to prevent axial movement, then positioning precision is improved, but thermal expansion causes excessive clamping pressure and potential damage
Solution Approach 1:
The patent replaces rigid clamping with elastic spring elements that provide dynamic positioning. The springs maintain precise axial positioning of the outer race while accommodating thermal expansions through elastic deformation, preventing excessive forces that could damage bearing components.
Solution Approach 2:
The spring elements act as beforehand cushioning by being pre-loaded to provide initial contact pressure while maintaining the capability to deflect under thermal expansion. This pre-cushioning prevents both excessive clearance and excessive clamping pressure, protecting the bearing components from damage.
3Temperature
If clearance is provided between the backup bearing inner race and the rotational portion, then thermal expansion accommodation is improved, but excessive clearance causes instability and potential mechanical contact
Solution Approach 1:
The spring-loaded outer race creates a dynamic clearance system that maintains optimal spacing between the inner race and rotational portion. As thermal conditions change, the spring deflection adjusts the clearance dynamically, preventing both excessive gaps that cause instability and insufficient clearance that causes mechanical contact.
Solution Approach 2:
The spring system provides inherent feedback by automatically adjusting the outer race position based on thermal expansion forces. The elastic elements sense temperature-induced dimensional changes and respond by modifying the clearance, maintaining stable operation without requiring external sensing or control 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
The system maintains stable clamping pressure and prevents mechanical contact, allowing for frictionless rotation and efficient operation even under thermal changes, ensuring the bearing balls can continue to roll without excessive pressure.
Implementation Method 1
A flat spring is carried by the stationary portion and abuts the back-up bearing. The flat spring may be configured to deflect upon an axial movement of the lateral side of the outer race. The flat spring can apply a preloaded force to the outer race.
Implementation Method 2
Expansions or contractions of an inner or outer race of a bearing can be compensated using particular springs providing a low profile and a proper stiffness.
Data Source
AI summary
The present disclosure describes a mechanical backup bearing system arrangement to work in conjunction with non-contact magnetic bearings and capable of coping with thermal expansions of the bearing components during operations. Expansions or contractions of an inner or outer race of a bearing can be compensated using particular springs providing a low profile and a proper stiffness. An electric machine system includes a rotational portion and a stationary portion. The electric machine further includes a magnetic bearing configured to support the rotational portion to rotate within the stationary portion. A mechanical back-up bearing resides in a cavity between the rotational portion and the stationary portion. A flat spring is carried by the stationary portion and abutting the back-up bearing.