Ball Screw End Deflector Noise Reduction
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Solution Overview
Problem
The existing ball screw systems using end deflectors generate collision noise when balls enter from the spiral groove of the screw shaft to the end deflector due to the presence of a step between the hook portion and the spiral groove, leading to interference and noise.
Innovation Solution
A ball screw design incorporating a pair of ball lifting portions positioned at approximately 180 degrees opposite positions to interpose the center of the spiral groove, which supports the balls and disperses the impact to two parts, reducing collision noise. The ball lifting portions are inclined and positioned outward in the radial direction to minimize collision angles and eliminate noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hook portion is provided in the end deflector to scoop balls into the circulation path, then balls can be guided from the spiral groove to the circulation path, but a step is formed between the hook portion and the spiral groove causing collision noise when balls abut on the step
Solution Approach 1:
The ball lifting function is divided into two separate ball lifting portions positioned at opposite sides of the spiral groove, each lifting balls from different locations. This segmentation disperses the impact points and reduces collision noise while maintaining effective ball guidance into the circulation path
Solution Approach 2:
The ball lifting portions are positioned in the radial direction outward from the mountain part of the spiral groove, utilizing the radial dimension to lift balls without interfering with the spiral groove path. This dimensional approach eliminates the need for a hook portion protruding into the groove, removing the step that causes collision noise
2Productivity
If the hook portion is positioned to effectively scoop balls, then ball circulation is improved, but interference between the hook portion and the movable screw shaft occurs requiring a gap that reduces precision
Solution Approach 1:
The ball lifting function is extracted from the hook portion configuration and implemented through ball lifting portions positioned outward in the radial direction. This extraction eliminates the interference problem with the movable screw shaft while maintaining ball circulation efficiency, as the lifting portions do not protrude into the spiral groove path
Solution Approach 2:
The ball lifting portions act as intermediary elements that lift balls from the spiral groove without direct contact or interference with the screw shaft. By positioning these lifting portions outward in the radial direction, they mediate the ball transfer process without requiring clearance gaps, thereby maintaining positioning precision
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
The solution effectively suppresses collision noise by dispersing the impact across two parts and reducing the collision angle, resulting in lower noise levels compared to traditional hook-based systems, while maintaining a simplified structure for smooth ball lifting.
Implementation Method 1
the impact at the time of abutting on the ball lifting portions is dispersed to two parts. Therefore, even when the collision noise is generated at the time of abutting on the ball lifting portions, the collision noise will be lower
Data Source
AI summary
A ball screw includes a nut, a screw shaft, an end deflector attached to the nut, plural balls, and a pair of ball lifting portions. A spiral groove is formed at an outer peripheral surface in the screw shaft. The plural balls roll along the spiral groove. The pair of ball lifting portions is provided at the end deflector so as to interpose a width center of the spiral groove. The pair of ball lifting portions supports the balls by a first part of one of the pair of ball lifting portions and a second part of other of the pair of ball lifting portions being apart from each other in a width direction of the spiral groove so as to interpose the width center of the spiral groove between the first and second parts to thereby lift the balls from the spiral groove.