Ball Screw End Deflector Assembly With Offset Insertion Fit
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Solution Overview
Problem
The assembly of an end deflector to a nut body in a ball screw is hindered by a reduced fitting gap, leading to decreased workability and increased risk of damage to protruding pieces, which affects the accuracy and yield of the assembly process.
Innovation Solution
The end deflector is designed with a main portion having an offset front-side portion and a shoulder portion, allowing for a loosely engaged initial insertion with a radial gap, reducing the likelihood of protruding pieces hitting the nut body during assembly, and featuring a flange portion and rib portion for enhanced bending rigidity and positional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the fitting gap between the deflector holding recess and the end deflector is reduced to improve assembly position accuracy, then the assembly accuracy is improved, but the workability of aligning and inserting the end deflector deteriorates
Solution Approach 1:
The outer circumferential surface of the end deflector's main portion is segmented into two distinct regions: a front-side portion that is offset inward in the radial direction, and a rear-side portion that is fitted to the deflector holding recess. This segmentation allows the front portion to lead insertion with a radial gap, improving workability, while the rear portion ensures accurate positioning when engaged with the recess.
Solution Approach 2:
The front-side portion of the outer circumferential surface is designed to be offset inward in the radial direction before insertion, creating a radial gap that facilitates easier alignment and insertion of the end deflector into the deflector holding recess. This preliminary geometric configuration prepares the assembly interface for smoother operation.
2Manufacturing precision
If the fitting gap is reduced to improve assembly accuracy, then the assembly precision is improved, but the protruding pieces are more likely to be damaged by hitting the nut body
Solution Approach 1:
The outer circumferential surface is divided into front-side and rear-side portions with different radial positions. The front-side portion's inward offset creates a radial gap that acts as a buffer zone, preventing the protruding pieces from contacting and damaging against the nut body during the insertion process, while the rear-side portion provides accurate positioning.
Solution Approach 2:
The radial gap created by the inward offset of the front-side portion serves as a cushioning space before the rear-side portion engages with the deflector holding recess. This gap prevents direct impact between the protruding pieces and the nut body, protecting against damage during assembly.
Data Source
AI summary
An end deflector includes a main portion including a ball delivery path that delivers balls between a rolling path and a ball return path, a tongue portion that guides the balls from the rolling path to the ball delivery path, and a pair of protruding pieces, that extend in the circumferential direction of each nut body from either side of the tongue portion with respect to the axial direction and define a ball guide groove that extends between the ball delivery path and the rolling path in cooperation with an inner circumferential surface of a deflector holding recess formed in a nut body, the main portion has an outer circumferential surface which opposes an inner circumferential surface of the deflector holding recess in the radial direction, a front-side portion of the outer circumferential surface with respect to a direction of insertion into the deflector holding recess is offset inward in the radial direction, and at least a rear-side portion of the outer circumferential surface with respect to the direction of insertion into the deflector holding recess is fitted to the inner circumferential surface of the deflector holding recess.