Axial Bearing Softener for Hyperstatic Transmission Loads
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Solution Overview
Problem
Mechanical transmissions with static and rotating parts under hyperstatic conditions face overload due to external loads and temperature effects, leading to inefficiencies and component stress, as existing solutions either increase mass and power requirements or are costly and difficult to manufacture.
Innovation Solution
A tunable axial softener system is introduced to the static component, comprising a rigid sleeve with a shim and biasing elements, allowing controlled axial movement between the static and rotatable components without altering the bearing contact angle, enabling the use of smaller, lighter components and maintaining bearing preload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thin large disks (flectors) are installed on rotating parts to manage hyperstaticism and misalignment, then hyperstatic conditions are partially managed, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent introduces a system softener as an intermediary element positioned between the bearing and the rigid sleeve. This softener comprises a linear stack of biasing elements (springs) and shims that act as a mediator to absorb axial hyperstatic forces, preventing them from being transmitted to the bearing and rotating components. The softener effectively decouples the rigid connection, allowing controlled axial movement while maintaining radial support.
Solution Approach 2:
The patent changes the axial stiffness parameter of the system by introducing compliant biasing elements in series with the rigid bearing support. The softener creates a tuned axial compliance that allows the system to accommodate thermal expansion and misalignment while maintaining proper bearing preload. The shim thickness and spring stiffness are specifically selected to achieve the desired axial softening effect.
2Reliability
If components are sized to account for overload in hyperstatic systems, then reliability is improved, but weight and mass increase
Solution Approach 1:
The patent applies beforehand cushioning by pre-installing the system softener with biasing elements and shims that are designed to absorb anticipated axial overloads before they reach the bearing and rotating components. The softener acts as a protective cushion that limits the maximum axial force transmitted to sensitive components, allowing them to be sized for normal operating conditions rather than peak overload conditions.
3Power
If a rigid axial connection is created through splined connections with friction, then torque transmission is improved, but hyperstatic conditions create stress on static and rotating parts
Solution Approach 1:
The patent segments the axial connection into two functional zones: a rigid radial support zone provided by the bearing for torque transmission, and a compliant axial zone provided by the system softener. This segmentation allows the bearing to handle radial loads and torque while the softener independently manages axial forces, preventing stress concentration on the splined connections and rotating parts.
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 solution effectively manages hyperstatic conditions by reducing component stress and size, allowing for efficient torque transmission and handling external loads without increasing mass or altering bearing dynamics, making it suitable for turboprop and rotorcraft applications.
Implementation Method 1
A system softener is disposed in the static component wherein the outer race is disposed between first and second biasing elements in a rigid sleeve
Data Source
AI summary
An axially hyperstatic system softener for a transmission comprising a static component and a rotatable component mounted to each other by a double ball bearing having an outer race and an inner race includes first and second biasing elements in a rigid sleeve with the outer race disposed between the first and second biasing elements. The rotatable component includes two shafts splined together with the static component mounted to one of the shafts by the bearing double ball bearing. A shim between one of the biasing elements and the sleeve enables tuning the softener.