Open Nut Ball Screw with Two-Piece Circulator Assembly
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Solution Overview
Problem
Existing ball screw assemblies with open nuts face manufacturing precision issues due to sagging screws and complex manufacturing processes for one-piece circulator structures, leading to deflection and improper ball rolling.
Innovation Solution
A two-piece circulator structure for the open nut, comprising an inner and outer member with through holes and slots, allowing for simplified assembly and manufacturing, and enabling easier ball filling without additional elements, while allowing for material flexibility and reduced manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a one-piece circulator structure is used, then the structure is simple, but the manufacturing process becomes complex and time-consuming due to additional insertion members and mold requirements
Solution Approach 1:
The circulator is divided into two separate pieces: an inner circulator and an outer circulator. The inner circulator includes an inner member with through holes and through slots, while the outer circulator includes an outer member with arc-shaped sliding grooves. This segmentation eliminates the need for complex one-piece molding and insertion members, significantly simplifying the manufacturing process while maintaining structural functionality.
2Reliability
If supporting holders are positioned away from the screw, then the resilient mechanism can provide support, but the screw sags due to its own weight causing deflection and improper ball rolling
Solution Approach 1:
The invention extracts and removes the supporting holder and resilient mechanism from the ball screw assembly. By using a open nut design with two circulators, the supporting holder is no longer needed, eliminating the sagging problem and associated precision issues while maintaining the necessary support function through the circulator structure.
3Reliability
If additional resilient mechanisms are configured at supporting holders, then support can be provided, but the device complexity and manufacturing cost increase
Solution Approach 1:
The resilient mechanism and supporting holder are completely removed from the assembly. The open nut structure with two circulators performs both the ball circulation function and provides necessary support, eliminating the need for separate resilient mechanisms and reducing overall device complexity.
Solution Approach 2:
The circulator structure serves multiple functions: it circulates balls through the ball race and simultaneously provides structural support for the screw, replacing the need for separate supporting holders and resilient mechanisms. This multi-functionality reduces the number of components and simplifies the overall assembly.
Data Source
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AI summary
An open nut (20) and a ball screw assembly having the open nut (20) are provided. The ball screw assembly includes a guider (10), the open nut (20), and a ball circulating assembly (30). The open nut (20) includes an axial cylinder (21), an open shield (22), and two circulators (23). The two circulators (23) are respectively disposed on a first axial wall (212) and a second axial wall (213) of the axial cylinder (21) with an axial opening (211). Each of the circulators (23) includes an inner member (231) and an outer member (232). The inner member (231) and the outer member (232) are assembled to each other and are respectively in communication with an inner ball race between the guider (10) and the open nut (20) and an outer ball race (O) of the open nut (20). Therefore, the inner ball race, ball races (L) of the two circulators (23), and the outer ball race (O) form a ball circulating race, and the ball circulating assembly (30) rolls in the ball circulating race.