Ball Screw Spring Support Using a Larger Stopper Ball
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Solution Overview
Problem
The existing ball screw apparatus experiences coil spring distortion and wear due to its orientation instability, particularly when subjected to high axial loads, which affects efficient screw power transmission and leads to potential interference with the ball screw shaft.
Innovation Solution
The ball screw apparatus incorporates a coil spring with a first end engaging the ball train and a second end supported by a stopper, featuring a stopper ball with a larger diameter than the main balls to stabilize the coil spring orientation, preventing distortion and wear by ensuring proper alignment and engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the coil spring is housed in the raceway between the ball screw shaft and the ball nut, then the coil spring can support the ball train, but the coil spring shape is distorted and it may interfere with the ball screw shaft causing wear
Solution Approach 1:
A stopper ball is introduced as an intermediary element between the coil spring and the ball screw shaft. This stopper ball prevents direct contact between the coil spring and the ball screw shaft, eliminating the harmful interference and wear while maintaining the coil spring's support function for the ball train.
Solution Approach 2:
The support function is segmented into two distinct components: the coil spring provides axial support for the ball train, while the stopper ball prevents radial interference with the ball screw shaft. This segmentation allows each component to perform its specific function without causing harmful effects to the other.
2Device complexity
If a standard-sized ball is used to support the coil spring, then the structure is simple, but the coil spring orientation is unstable under high axial loads
Solution Approach 1:
The stopper ball is designed with a larger diameter than standard balls to provide enhanced radial support. This local quality change (larger diameter) specifically at the coil spring support position improves orientation stability under high axial loads without significantly increasing overall device complexity.
3Productivity
If the coil spring contracts under high axial load, then efficient screw power transmission is achieved, but the coil spring distortion increases causing potential interference with the ball screw shaft
Solution Approach 1:
The stopper ball is positioned in advance to prevent direct contact between the coil spring and the ball screw shaft. This beforehand cushioning ensures that even when the coil spring contracts and distorts under high axial loads, it cannot interfere with the ball screw shaft, allowing efficient power transmission without harmful side effects.
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 configuration stabilizes the coil spring orientation, preventing distortion and wear, thereby enhancing efficient screw power transmission and reducing the risk of interference with the ball screw shaft, ensuring reliable operation under varying axial loads.
Implementation Method 1
when the ball screw is rotationally driven with a high axial load imposed on the ball screw shaft, the coil spring contracts to allow the ball screw to move with the balls rolling with respect to both the ball nut and the ball screw shaft
Implementation Method 2
at least one stopper ball interposed between the stopper and the second end of the coil spring and having a larger diameter than the main ball
Data Source
AI summary
In a ball screw apparatus, a ball train including a plurality of main balls is housed in a raceway between a ball track of a ball nut and a ball track of a ball screw shaft. A coil spring housed in the raceway includes a first end that engages with an end of the ball train and a second end supported by a stopper (a first recessed portion, a protruding portion, or the like) of the ball nut. A stopper ball having a diameter larger than the diameter of the main ball is interposed between the stopper and the second end of the coil spring.