Segmented Ball Screw Nut Structure for Precise Ball Recirculation
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Solution Overview
Problem
The existing ball screw devices face challenges in assembly complexity, positioning accuracy, and the difficulty in forming high-accuracy endless circulation paths for balls, which affects the moving accuracy of the nut member relative to the screw shaft.
Innovation Solution
A ball screw device design featuring a nut member composed of multiple nut components with identical raceway forming surfaces and abutment surfaces, allowing for easy assembly and production through plastic working, and enabling the formation of multiple circuits of endless circulation paths with high accuracy by superposing components with matching shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If insertion rings are fixed by bending edge portions of the nut member, then the nut member can be assembled, but assembly time and effort increase and positioning accuracy of insertion rings deteriorates
Solution Approach 1:
The nut member is divided into multiple nut components (first nut component and second nut component) that can be assembled separately. Each component has its own through-hole and can be positioned independently, allowing for easier assembly while maintaining positioning accuracy through the joining surfaces with abutment surfaces.
Solution Approach 2:
Joining surfaces with abutment surfaces are introduced as intermediary elements between the nut components and the insertion rings. The abutment surfaces provide precise positioning and support for the insertion rings, eliminating the need for complex bending operations while ensuring high positioning accuracy.
2Stability of the object's composition
If insertion rings are fixed by bending edge portions, then the structure can be maintained, but the endless circulation path for balls cannot be formed with high accuracy
Solution Approach 1:
The nut member is segmented into multiple components that are joined together using abutment surfaces. This segmentation allows the endless circulation path to be formed across multiple components with high precision, as each component can be manufactured and positioned separately with accurate joining surfaces.
Solution Approach 2:
The design extends the circulation path across multiple nut components in the axial direction, creating a multi-dimensional circulation path. The abutment surfaces ensure precise alignment in this additional dimension, enabling high-accuracy formation of the endless circulation path that extends beyond a single nut component.
3Ease of manufacture
If multiple nut components are used with joining surfaces, then assembly is simplified and positioning accuracy is enhanced, but device complexity increases
Solution Approach 1:
The nut member is divided into multiple identical or similar nut components with standardized joining surfaces. This segmentation simplifies manufacturing as each component can be produced using the same process, and assembly is facilitated by the standardized abutment surfaces that guide precise positioning without requiring complex alignment procedures.
Solution Approach 2:
Each nut component is designed with universal joining features (abutment surfaces) that can be repeatedly used across multiple components. This universality allows the same component design to be assembled in series to create longer circulation paths, reducing the need for different specialized components and thereby reducing overall device complexity despite the increased number of components.
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 design simplifies assembly, enhances positioning accuracy, and allows for the easy increase in the number of circulation paths, resulting in improved moving accuracy and efficiency in converting rotary motion to translational motion.
Implementation Method 1
a ball screw device including: a plurality of balls; a screw shaft having a spiral rolling groove in an outer peripheral surface thereof, the spiral rolling groove being configured to allow the plurality of balls to roll therein
Data Source
AI summary
Provided is a ball screw device which enables easy production and assembly of a nut member and formation of an endless circulation path for balls in the nut member with high accuracy. The nut member includes a plurality of nut components arranged in a superposed manner along an axial direction of a screw shaft. At a boundary portion between the nut components which are adjacent to each other, a raceway path for balls extending around a periphery of the screw shaft is formed. A joining surface of each of the nut components used for joining with another one of the nut components includes: a raceway forming surface which is annularly formed around the through hole; and an abutment surface for joining which is formed on an outer side in a radial direction with respect to the raceway forming surface.