Elevator Sheave with Y-Shaped Intermediate Members
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Solution Overview
Problem
The existing sheave mechanism for elevators experiences bending deformation and oscillation due to uneven stiffness distribution, leading to reduced ride comfort and increased abrasion, as the portions outside the holes in the radial direction have lower stiffness than the connecting members, causing periodic bending towards the center during rotation.
Innovation Solution
A sheave design with a cylindrical base member and a coaxial winding member, connected by intermediate members with a Y-like or V-like shape, which support the winding member at multiple points, reducing the distance between adjacent supported portions and enhancing structural strength, thereby minimizing bending deformation and oscillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If connecting members are used to connect the sheave and bearing portion, then the sheave structure is formed, but bending deformation occurs in the portions outside the holes due to lower stiffness, causing oscillation and degraded ride comfort
Solution Approach 1:
The sheave is divided into multiple segments (base member, winding member, and intermediate members) connected through bearing portions. This segmentation allows each component to be optimized independently while working together to reduce overall deformation and improve ride comfort.
Solution Approach 2:
Different regions of the sheave are designed with different properties. The intermediate members have varying cross-sectional areas and thicknesses at different locations to optimize stiffness distribution, with thicker sections at connection points and thinner sections in non-critical areas, reducing unnecessary weight while maintaining structural integrity.
2Device complexity
If multiple holes are formed between connecting members, then the sheave structure is created, but the portions outside the holes have reduced stiffness leading to periodic bending deformation during rotation
Solution Approach 1:
The intermediate members feature curved or tapered cross-sections rather than straight uniform shapes. This curvature optimizes the distribution of material to resist bending moments while reducing weight, with the curved geometry providing better structural efficiency in resisting the periodic loads during rotation.
3Shape
If the sheave has portions with alternating stiffness (outside holes vs. outside connecting members), then the sheave is formed, but oscillation is transmitted to the car during rotation
Solution Approach 1:
The cross-sectional parameters (area, thickness, shape) of the intermediate members are continuously varied along their length to optimize the stiffness distribution. This gradual parameter change smooths out the stiffness variations that would otherwise cause oscillation, creating a more uniform dynamic response during rotation.
Data Source
AI summary
Provided is a sheave for a lift, including: a base member having a cylindrical shape; a winding member that is coaxial with the base member and has a cylindrical shape with a diameter larger than a diameter of the base member; and a plurality of intermediate members provided between the base member and the winding member in a radial direction of the winding member. Each of the plurality of intermediate members includes: a first end portion connected to the base member; a second end portion connected to the winding member; a third end portion connected to the winding member at a position different from a position at which the second end portion is connected to the winding member in a circumferential direction of the winding member; and a branch portion formed between the first end portion and each of the second end portion and the third end portion.