Ball Screw Circulation Structure for Small-Lead Stable Operation
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Solution Overview
Problem
Existing ball screw designs face challenges in maintaining stable operation due to weaknesses in the ball circulation part, particularly when applied to small lead or multi-thread specifications with a small ball pitch.
Innovation Solution
The design incorporates a nut with elongated holes in the notch portion, featuring a circulation part composed of first and second circulation components and a pipe, where the pipe enhances the strength of the direction changing part, and the elongated hole guides the balls for improved scoop-up functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a circulation component is manufactured by insert molding with two components physically connected, then the structure can be formed, but the design becomes complicated and the shape cannot be applied to small lead or multi-thread specifications with small ball pitch
Solution Approach 1:
The circulation component is divided into multiple independent parts: a circulation body and a separate reinforcement member. This segmentation allows each part to be manufactured independently using suitable processes, avoiding the complexity of multi-component insert molding while enabling the structure to adapt to different lead specifications and ball pitch requirements.
Solution Approach 2:
The reinforcement member is fitted into a recess formed in the circulation body, creating a nested structure. This allows the reinforcement member to be integrated into the circulation component without requiring complex physical connections, simplifying the overall design while maintaining structural integrity for various lead and ball pitch configurations.
2Device complexity
If the ball circulation groove is formed with standard depth and width, then the structure is simple, but the balls are peeled off when colliding with the inner surface of the direction changing portion
Solution Approach 1:
The circulation groove is designed with varying cross-sectional shapes along its length, creating different local geometries in different regions. The groove has a first cross-sectional shape in one region and a second cross-sectional shape in another region, allowing optimization of ball guidance and reduction of collision impacts at specific locations without complicating the overall structure.
Solution Approach 2:
The circulation groove extends in the axial direction of the nut with varying cross-sectional characteristics, utilizing the axial dimension to create progressive ball guidance. This dimensional approach allows the groove to smoothly guide balls through direction changes, preventing peeling off during operation while maintaining structural simplicity.
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 ensures a more stable operation by strengthening the ball circulation part and allows the ball screw to be applied to both small and large leads with a small ball pitch, enhancing its versatility.
Implementation Method 1
a pipe that is disposed in an abutting surface where the first circulation component and the second circulation component abut against each other, constitutes a part of the ball circulation path, and has a higher strength than materials of the first and second circulation components
Implementation Method 2
the nut is formed with, in the notch portion, an elongated hole that penetrates in a radial direction and whose longitudinal direction is formed along a lead angle and parts of both longitudinal side surfaces parallel to each other guide the balls
Implementation Method 3
a scoop-up part of the ball circulation path is constituted by the tongue portion of the first circulation component, the wall portion of the second circulation component, and the both longitudinal side surfaces of the elongated hole
Data Source
AI summary
A nut of a ball screw is formed with, in a notch portion, an elongated hole that penetrates in a radial direction, and whose longitudinal direction is formed along a lead angle and parts of both longitudinal side surfaces parallel to each other guide balls. A circulation part includes: a first circulation component that is disposed in the notch portion so as to abut against a bottom wall surface of the notch portion and has a tongue portion accommodated in the elongated hole; a second circulation component that is disposed in the notch portion so as to cover the first circulation component and accommodated in the elongated hole, and has a wall portion facing the tongue portion; and a higher strength pipe that is disposed in an abutting surface where the first and second circulation components abut against each other, constitutes a part of a ball circulation path.