Deflecting Device for Ball Screw Alignment
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Solution Overview
Problem
Conventional motion guide apparatuses, such as ball screw devices, face issues with ball bearing elements not being suitably guided due to misalignment and non-flushness between the circular cross-section deflecting channels and the helical groove portions of the screw shaft and ball nut, leading to inefficient sliding movement.
Innovation Solution
A motion guide apparatus featuring a ball nut with a helical groove and a returning channel, along with deflecting devices having U-shaped and circular cross-section deflecting pathways, which are anchored to the ball nut to form an endless guiding passage, ensuring proper alignment and smooth movement of ball bearing elements between the screw shaft and ball nut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional circular cross-section deflecting channels are used in deflecting elements, then the structure is simple to manufacture, but the ball bearing elements cannot be suitably guided due to misalignment with the helical groove portions
Solution Approach 1:
The deflecting device employs different cross-sectional shapes at different locations: the first deflecting channel has a circular cross-section for receiving balls from the helical groove, while the second deflecting channel has a non-circular cross-section for aligning with the returning channel. This local differentiation of geometric properties enables precise alignment and smooth ball flow through each section without requiring the entire device to be complex.
2Ease of operation
If the deflecting channels are made to align perfectly with the helical groove portions, then the ball bearing elements can be suitably guided, but the manufacturing complexity increases
Solution Approach 1:
The deflecting device is divided into multiple distinct components: a deflecting element with deflecting channels, and separate anchoring elements for attachment to the ball nut. This segmentation allows each component to be manufactured independently using standard processes, while the assembled structure achieves the complex alignment needed for smooth ball bearing element movement through the helical groove and returning channel.
3Productivity
If conventional deflecting elements with circular cross-section channels are used, then the device complexity is low, but the ball bearing elements experience misalignment and inefficient sliding movement
Solution Approach 1:
The invention changes the geometric parameters of the deflecting channels by using different cross-sectional shapes (circular vs. non-circular) at different locations. The first deflecting channel uses a circular cross-section optimized for receiving balls from the helical groove, while the second deflecting channel uses a non-circular cross-section optimized for aligning with the returning channel. This parameter variation maximizes ball circulation efficiency without requiring overly complex device architecture.
Data Source
AI summary
A motion guide device includes a ball nut attached onto a shaft and having helical grooves and a returning channel for forming an endless ball guiding passage and for receiving a number of ball bearing elements, two deflecting devices are engaged with the ball nut and each include a deflecting pathway communicative with the helical groove and the returning channel of the ball nut and each include a protrusion engaged with a recess of the ball nut for anchoring the deflecting devices to the ball nut, and the deflecting devices each include a connecting surface directed toward the helical groove of the ball nut for guiding the ball bearing elements to smoothly move between the helical groove of the ball nut and the deflecting pathways of the deflecting devices.