Rotary Shock Absorbing Stop Lock With Squeeze Film Bearing
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Solution Overview
Problem
Existing emergency stop mechanisms for rotary shafts in machines are costly, bulky, complex, and have limited applicability, particularly for lifting loads, especially when used to lift people, and require improvements in safety and cost-effectiveness.
Innovation Solution
A rotary shock absorbing stop and lock mechanism utilizing a squeeze film bearing with a converging escape path for hydraulic oil, featuring a stator assembly and rotor with offset lobes to decelerate and stop loads, and a resettable design using check valves and tapered splines for easy reengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional emergency stop mechanisms (redundant drive trains, self-binding multiple lift systems, external brakes, external locks) are used, then safety function is provided, but the device becomes costly, bulky, complex, and of limited applicability
Solution Approach 1:
The patent combines the shock absorbing function and the stop/lock function into a single integrated squeeze film bearing assembly. The stator and rotor lobes work together to provide both deceleration through fluid squeezing and final stopping through lobe contact, eliminating the need for separate brake and lock mechanisms.
Solution Approach 2:
The invention uses hydraulic fluid trapped between the stator and rotor lobes to provide shock absorption. As the rotor turns during overload, the fluid is squeezed through progressively smaller gaps, creating hydraulic resistance that decelerates the rotor smoothly without mechanical contact or wear.
2Reliability
If conventional emergency stop mechanisms are used, then safety function is provided, but the device becomes costly and bulky
Solution Approach 1:
The patent combines the shock absorbing function and the stop/lock function into a single integrated squeeze film bearing assembly. The stator and rotor lobes work together to provide both deceleration through fluid squeezing and final stopping through lobe contact, eliminating the need for separate brake and lock mechanisms.
Solution Approach 2:
The invention uses a thin film of hydraulic fluid between the stator and rotor lobes to provide shock absorption. This thin film mechanism replaces bulky mechanical brake systems while maintaining effective deceleration capability.
3Reliability
If the squeeze film bearing uses a converging escape path for hydraulic oil, then shock absorption is effective, but the mechanism requires precise manufacturing
Solution Approach 1:
The stator and rotor lobes are designed with asymmetric profiles where the stator lobe profile is the mirror image of the rotor lobe profile. This asymmetric design creates the converging escape path for hydraulic fluid that provides effective shock absorption while being manufacturable using standard precision machining techniques.
4Reliability
If the rotor lobes contact stator lobes to stop rotation, then the shaft is locked, but wear may occur at contact points
Solution Approach 1:
The hydraulic fluid in the squeeze film bearing provides cushioning during the deceleration phase, reducing the impact force when the rotor lobes contact the stator lobes. This prior cushioning minimizes wear at the contact points while ensuring reliable shaft locking.
Solution Approach 2:
The invention converts the potentially harmful direct impact of rotor-stator lobe contact into a beneficial controlled stopping mechanism. The hydraulic fluid first decelerates the rotor, then the lobe contact provides a positive mechanical stop, transforming what could be a wear-inducing impact into a controlled, low-wear stopping action.
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 mechanism provides a small footprint, high torque capacity, is cost-effective, and ensures fail-safe operation by decelerating and holding loads without wear, with a resettable design that maintains efficiency and reliability.
Implementation Method 1
The shock absorbing function is provided in the form of a squeeze film bearing that has a converging escape path for hydraulic oil, or the like.
Implementation Method 2
The space between the second plurality of convex surfaces and the first plurality of concave surfaces diverge from an inlet side through which a fluid is received in the space to an outlet side through which the fluid flows into an adjacent one of the plurality of cavities. At the outlet side the fluid is squeezed to a squeeze film thickness
Data Source
AI summary
A rotary shock absorber and stop apparatus includes a stator assembly for a rotor. The stator assembly includes an inner plate, an outer plate, and a stator plate assembled together to define a plurality of cavities. The stator assembly includes first lobes that extend radially inwardly from concave surfaces disposed between each of the first lobes. The rotor includes second lobes that have a second convex surface on a radially outer periphery that is offset relative to the first concave surface. Spaces are defined between the second convex surfaces and the first concave surfaces through which fluid flows between high-pressure chambers and low-pressure chambers.