Internal Recirculation Insert for Ball Screw Noise Reduction
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Solution Overview
Problem
Internal ball return systems in ball screw mechanisms often experience noise and vibration due to the movement of crossover blocks, which can misalign and affect ball recirculation, leading to friction and velocity issues.
Innovation Solution
An internal recirculation insert with securing arms and friction features, such as angular tabs or a rigid band, is used to securely hold the insert within the ball nut, maintaining alignment and reducing oscillation, thereby ensuring smooth ball transport between raceways without additional extensive machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a slip fit retention method is used for the crossover block, then the block can be easily installed and retained by ball recirculation, but the block moves during operation causing noise and vibration
Solution Approach 1:
The retention feature is segmented into multiple components: the crossover block itself, the radial bore in the ball nut, and the friction fit surface. This segmentation allows the block to be easily installed while the friction surface prevents movement during operation, resolving the contradiction between ease of installation and noise reduction.
Solution Approach 2:
The retention system transitions from a static slip fit to a dynamic friction-based retention where the constant recirculation of balls maintains the friction fit. This dynamic approach allows easy installation initially while preventing movement and noise during operation through the ongoing friction mechanism.
2Ease of manufacture
If the crossover block is allowed to move during operation, then installation is simplified, but ball alignment with the ball channel deteriorates
Solution Approach 1:
The alignment mechanism is segmented into the crossover block's ball channel and the ball nut's radial bore, with the friction fit surface providing the connection. This segmentation enables simple installation while maintaining precise alignment through the friction-based retention mechanism during operation.
Solution Approach 2:
The system uses the constant recirculation of balls to maintain the friction fit and alignment of the crossover block. The balls themselves serve to retain the block in the correct position, eliminating the need for complex retention features while ensuring continuous alignment.
3Object-generated harmful factors
If a secure retention feature is added to prevent crossover block movement, then noise and vibration are reduced, but the device complexity increases
Solution Approach 1:
The retention feature is merged with the radial bore structure of the ball nut. The friction fit surface is integrated into the bore design, and the securing arms are formed as part of the crossover block itself. This merging reduces device complexity by eliminating separate retention components while still preventing noise and vibration.
Solution Approach 2:
The radial bore serves multiple functions: it guides the balls, retains the crossover block through friction fit, and provides structural support. The crossover block itself serves as both the ball recirculation pathway and the retained component. This multi-functionality reduces the need for additional retention features, maintaining simplicity while reducing noise and vibration.
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 secure fit of the internal recirculation insert minimizes noise and vibration, maintaining constant alignment and improving the smooth recirculation of balls, reducing friction and ensuring efficient operation of the ball screw assembly.
Implementation Method 1
a friction feature is included or added to the internal recirculation insert... This feature may include any number of elements, such as; an angularly extending tab machined or molded into the sides of the internal recirculation insert in contact with the walls of the radial bore of the ball nut
Data Source
AI summary
An internal ball recirculation insert for a ball screw assembly. The ball screw assembly having a ball nut with at least one radial bore though it, a ball screw and load bearing balls. The ball screw and ball nut having complimental helical grooves, forming helical ball raceways when the ball screw and ball nut are assembled. The internal ball recirculation insert sized to fit into the radial bore of the ball nut, having a body portion, securing arms, a ball channel for channeling balls from one ball raceway to another and a friction or retention device around the circumference of the body portion. The friction device extending outwardly from a side wall of the recirculation insert, and contacting a wall of the radial bore in the ball nut.