Segmented Ball Screw Nut Structure for Accurate Endless Ball Circulation
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Solution Overview
Problem
The existing ball screw devices face challenges in assembling the nut member accurately and efficiently, leading to difficulties in forming a high-accuracy endless circulation path for balls, which affects the moving accuracy of the nut member relative to the screw shaft.
Innovation Solution
The ball screw device is designed with nut components having raceway forming surfaces of the same shape, allowing for easy production and assembly through plastic working, and enabling the formation of an accurate endless circulation path by superposing these surfaces without gaps, with abutment surfaces for joining to facilitate precise assembly and easy increase in the number of circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pair of insertion rings is fixed to the hollow portion of the nut member by bending the edge portions of the nut member, then the insertion rings can be secured in position, but it takes time and effort to assemble the nut member and positioning accuracy of the insertion rings deteriorates
Solution Approach 1:
The insertion rings are pre-fixed to the nut member before assembly, with their positions predetermined during manufacturing. This preliminary positioning eliminates the need for time-consuming assembly operations and ensures high positioning accuracy is maintained throughout the assembly process.
Solution Approach 2:
A fixing member is introduced as an intermediary element to secure the insertion rings to the nut member. This fixing member simplifies the assembly process by providing a straightforward attachment mechanism that ensures accurate positioning without requiring complex bending operations.
2Manufacturing precision
If the pair of insertion rings is fixed inside the hollow portion of the nut member, then the insertion rings are secured, but it is difficult to improve positioning accuracy of the pair of insertion rings
Solution Approach 1:
The insertion rings are pre-positioned and fixed to the nut member during manufacturing with predetermined accuracy. This preliminary action ensures high manufacturing precision is achieved without requiring complex assembly procedures, as the positioning is established once during production and maintained throughout the product lifecycle.
3Quantity of substance
If multiple nut components are superposed to increase the number of circuits, then the number of circuits can be increased, but assembly complexity increases
Solution Approach 1:
The nut member is divided into multiple nut components that can be superposed to create multiple circuits. Each nut component contains insertion rings with the same predetermined positioning, allowing the system to achieve multiple circuits while maintaining simplicity in assembly through standardized, interchangeable parts.
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 enables high-accuracy formation of the endless circulation path, simplifies assembly, and allows for an increase in the number of circuits, thereby improving the moving accuracy of the nut member relative to the screw shaft, enhancing the overall performance of the ball screw device.
Implementation Method 1
the nut components can easily be produced by plastic working such as forging with dies
Implementation Method 2
the abutment surface for joining formed on the outer side of the raceway forming surface is brought into abutment against the abutment surface for joining of another nut component
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Provided is a ball screw device which enables easy production and assembly of a nut member (3) and formation of an endless circulation path for balls in the nut member (3) with high accuracy. The nut member (3) includes a plurality of nut components (5,6) arranged in a superposed manner along an axial direction of a screw shaft (2). At a boundary portion between the nut components (5, 6) which are adjacent to each other, a raceway path (30) for balls (4) extending around a periphery of the screw shaft (2) is formed. A joining surface of each of the nut components (5, 6) used for joining with another one of the nut components includes: a raceway forming surface (53, 62) which is annularly formed around the through hole; and an abutment surface (50,60) for joining which is formed on an outer side in a radial direction with respect to the raceway forming surface (53, 62).