Ball Turn Groove Geometry for Durable Motion Guides
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Solution Overview
Problem
The known motion guide apparatus faces challenges with the movement of balls in the turn portions, which affects the overall performance and durability of the turn portions.
Innovation Solution
The motion guide apparatus includes a rail member with a rolling groove and a block with a rolling groove, return portion, and turn portion. The balls are placed in a circulation path that includes the rolling path, return portion, and turn portion. The balls are sandwiched between the rail member's rolling groove and the block's turn groove to change their course, and the angles formed by the rail member and block ensure that the balls are smoothly guided through the turn groove.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the balls are guided through the turn portion using conventional design, then the structure is simple, but the movement performance and durability of the turn portion deteriorate
Solution Approach 1:
The turn groove is designed with different geometric characteristics in different regions: the first region has a specific curvature radius to guide balls from the rolling groove, while the second region has a different curvature radius to guide balls into the return groove. This local differentiation of geometric properties optimizes ball movement performance in each specific region while maintaining overall structural efficiency.
Solution Approach 2:
The turn groove employs curved paths with specifically designed radius of curvature to guide the balls smoothly through the turn portion. The first and second regions of the turn groove have different curvature radii that match the ball geometry and movement requirements, enabling smooth transition without impact or jamming, thereby improving durability.
2Ease of operation
If the turn groove geometry is optimized for smooth ball movement, then the movement performance improves, but the manufacturing complexity increases
Solution Approach 1:
The turn groove geometry is defined by specific parameter relationships: the radius of curvature in the first region is set to be larger than that in the second region, and both are related to the ball radius. These parameter specifications provide clear manufacturing guidelines while achieving smooth ball movement through the turn portion.
3Productivity
If the turn groove is designed with multiple regions and specific curvature radii, then the ball movement performance improves, but the device structure becomes more complex
Solution Approach 1:
The turn groove is divided into two distinct regions: a first region with a larger radius of curvature for receiving balls from the rolling groove, and a second region with a smaller radius of curvature for guiding balls into the return groove. This segmentation allows each region to be optimized for its specific function, improving overall circulation efficiency while maintaining a relatively compact structure.
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 allows for improved performance in the movement of balls through the turn groove and enhanced durability of the turn groove, ensuring smooth operation and extended service life.
Implementation Method 1
A plurality of balls is interposed between the rail member and the block in such a manner as to be capable of rolling motion
Implementation Method 2
the balls are sandwiched between a wall surface of the rolling groove of the rail member and a wall surface of at least part of a turn groove of the turn portion of the block to change the course of the balls
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
Provided is a motion guide apparatus capable of improving performance such as the repeated durability of and movement in a turn portion. The motion guide apparatus sandwiches a ball (3) between a wall surface of a rolling groove (7) of a rail member (2) and a wall surface of a turn groove (10) of a block (4) to change the course of the ball (3) that has moved along a rolling path. α + β < 180° is satisfied where α is a rail member-side angle, and β is a block-side angle.