Ball Screw Nut Circulation Layout for Shorter Axial Length
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Solution Overview
Problem
The existing ball screw devices are unable to downsize the nut in the axial direction due to the limitations of reducing the distance between the centers of the tubes, which causes the annular walls to contact each other.
Innovation Solution
A ball screw device design that includes a nut with internal and external threads, outer and inner peripheral raceway surfaces, and circulation components with communication paths and partition walls, allowing for the reduction of the distance between the centers of the communication paths and thus the nut's axial size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the distance between centers of the two tubes is reduced to downsize the nut in the axial direction, then the nut axial size is reduced, but the annular walls of the tubes come into contact with each other
Solution Approach 1:
The circulation component is divided into multiple functional parts: the nut body, separate annular walls for each rolling path, and communication paths with partition walls. This segmentation allows each part to be optimized independently, enabling reduced axial size while maintaining structural integrity and preventing wall contact through proper spacing design.
Solution Approach 2:
The patent transitions from a single large circulation component to multiple smaller circulation paths arranged in different spatial dimensions. By creating separate communication paths with partition walls and positioning them at different radial and axial positions, the design achieves compactness in the axial direction while maintaining adequate spacing to prevent annular wall contact.
2Length of moving object
If the width of the internal thread or external thread is reduced to downsize the nut, then the axial distance between rolling paths is reduced, but the distance between tube centers must also be reduced causing wall contact
Solution Approach 1:
The communication paths are designed with flexible positioning and adjustable geometry, allowing the distance between tube centers to be optimized independently of the thread width. The partition walls and communication path configuration can be dynamically adjusted to maintain adequate spacing even when thread dimensions are reduced for compactness.
3Productivity
If two tubes are used as circulation components, then ball circulation is achieved, but the axial distance between tube centers cannot be reduced due to wall contact
Solution Approach 1:
Partition walls are introduced as intermediary structures between the two circulation paths. These partition walls act as mediators that allow the two ball circulation paths to coexist in close proximity without direct contact between annular walls, enabling reduced center distance while maintaining functional independence of each circulation path.
Data Source
AI summary
A ball screw device includes a nut having an internal thread and two outer peripheral raceway surfaces, a screw shaft having an external thread and two inner peripheral raceway surfaces, a plurality of balls arranged on two rolling paths, and two circulation components provided at one end and the other end of the nut to circulate the balls. The internal thread and the external thread hold the balls. The nut has a cylindrical shape and includes a cylindrical body having the external thread and the outer peripheral raceway surfaces, and two return paths penetrating the cylindrical body in an axial direction parallel to an axis of the screw shaft. Each of the circulation components includes a main body fixed to the cylindrical body of the nut, two communication paths penetrating the main body and communicating the two rolling paths and the two return paths, a communication path partition wall between the two communication paths so as to partition the two communication paths, and two tongues protruding from the main body to the rolling paths.