Ball Screw Turning Unit With Lightweight High-Ratio Driven Pulley
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing turning units with increased reduction ratios face challenges in maintaining a lightweight and compact design due to the complexity and weight increase of the driven pulley, particularly when the outer diameter is enlarged.
Innovation Solution
The design incorporates a ball screw mechanism with a simplified circulation path configuration using through holes and passages in the ball screw nut, along with a thin portion on the driven pulley and a pressing lid to maintain weight balance, allowing for increased reduction ratios without excessive weight or complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the outer diameter of the driven pulley is increased to increase the reduction ratio, then the reduction ratio is improved, but the weight of the driven pulley increases
Solution Approach 1:
The circulation path is divided into two separate components: a first passage formed in the ball screw nut and second passages formed in circulation members. This segmentation allows the circulation function to be distributed, enabling the driven pulley to be thinner and lighter while maintaining the necessary circulation capability for increased reduction ratio.
Solution Approach 2:
The circulation path transitions from being entirely within the circulation member to a three-dimensional configuration spanning multiple components (ball screw nut and circulation members). This dimensional redistribution allows the driven pulley to reduce thickness in the radial direction while maintaining circulation functionality.
2Device complexity
If the entire circulation path is configured by a passage formed inside the circulation member, then the circulation function is simplified, but the shape of the circulation member becomes complicated
Solution Approach 1:
The circulation path is segmented into a first passage in the ball screw nut and second passages in circulation members. This division simplifies the shape of individual circulation members by removing the requirement for them to contain the entire circulation path, while the overall circulation function remains integrated through the combined passages.
3Weight of moving object
If the driven pulley is made thinner to reduce weight, then the weight is reduced, but the structural strength may be compromised
Solution Approach 1:
The driven pulley is merged with the ball screw nut assembly, where the ball screw nut provides structural support and the driven pulley can be optimized for minimal thickness. The integration allows the stronger ball screw nut to compensate for the reduced strength of the thinner driven pulley, maintaining overall structural integrity.
Solution Approach 2:
The system uses different material properties and structural configurations in the driven pulley and ball screw nut to create a composite assembly where each component is optimized for its specific function, allowing the driven pulley to be thin and light while the ball screw nut provides the necessary structural strength.
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 configuration effectively suppresses the weight increase of the driven pulley and simplifies the shape of the circulation member, ensuring smooth rotation and reduced weight, even with larger pulley diameters.
Implementation Method 1
a ball screw mechanism that has a ball screw nut coupled to the driven pulley so that the ball screw nut is integrally rotatable, and a plurality of balls disposed in a ball raceway that has a helical shape and that is provided such that a screw groove provided on an outer periphery of the turning shaft face a screw groove provided on an inner periphery of the ball screw nut, and that converts a rotation of the ball screw nut into reciprocating movement of the turning shaft
Implementation Method 2
a belt mechanism having a driving pulley coupled to a motor, a driven pulley disposed on an outer periphery of the turning shaft so that the driven pulley is rotatable, and a belt that is wound around between the driving pulley and the driven pulley
Data Source
AI summary
A ball screw nut has a pair of through holes and a first passage that allows the through holes to communicate with each other and that opens radially outward. In each of the through holes, a ball screw mechanism has a circulation member having a second passage in which a ball can move between a ball raceway and the first passage. The ball screw mechanism has a circulation path for communicating the two connection points set on the ball raceway by the first passage and each of the second passages. A driven pulley has a thin portion that defines a radial clearance between an inner periphery of the driven pulley and an outer periphery of the ball screw nut. The ball screw mechanism has a pressing lid that presses down each of the circulation members from the outer periphery of the ball screw nut and that covers the first passage.