Ball Screw Deflection Piece for Precise Low-Friction Ball Transfer
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Solution Overview
Problem
Existing ball screws in clutch release systems face challenges in achieving high mechanical precision and minimizing friction during the transfer of balls between spindle drive parts, particularly under conditions of varying production parameters and exposure to centrifugal forces and vibrations.
Innovation Solution
A ball screw design featuring a deflection piece inserted into a depression of one spindle drive part with contact faces that project laterally, allowing for precise positioning and low friction transfer of balls, supported on the outer or inner circumference, and manufactured from plastics for efficient injection molding, with features like deflection lugs and a contoured top face to maintain function even when partially disengaged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the deflection piece lies on the base of the depression, then the positioning is simple, but mechanical precision and ball transfer reliability deteriorate
Solution Approach 1:
The deflection piece is positioned not on the base of the depression but on lateral contact faces that project beyond the depression. This dimensional change from base contact to lateral face contact enables precise positioning while maintaining ease of manufacture through injection molding.
Solution Approach 2:
The lateral contact faces act as an intermediary positioning mechanism between the deflection piece and the depression base. This intermediary structure provides stable positioning and reliable ball transfer without requiring the deflection piece to rest directly on the depression base.
2Manufacturing precision
If the deflection piece contacts the track surface, then mechanical precision improves, but friction increases
Solution Approach 1:
The deflection piece has differentiated surface properties: the lateral contact faces provide high friction for stable positioning, while the top face provides low friction for ball transfer. This local quality differentiation resolves the contradiction between mechanical precision and friction.
Solution Approach 2:
The friction parameter is changed locally on the deflection piece surface. The lateral contact faces have high friction coefficients for positioning, while the top face has low friction coefficients (enhanced by lubricant) for ball transfer, resolving the contradiction between precision and friction.
3Object-generated harmful factors
If the gap between deflection piece and thread is large, then friction decreases, but lubricant retention deteriorates
Solution Approach 1:
The gap parameter is optimized to a specific small dimension that simultaneously achieves low friction and good lubricant retention. This parameter optimization resolves the contradiction between friction reduction and lubricant retention.
4Ease of manufacture
If the deflection piece is easily removable from mold, then manufacturing ease improves, but positioning precision may deteriorate
Solution Approach 1:
The deflection piece is designed as a separate injection-molded component with integrated deflection lugs that provide both easy mold removability and precise positioning. The segmentation of the molding process from final assembly allows both ease of manufacture and precision to be achieved.
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 design achieves high mechanical precision, low friction, and lubricant retention, ensuring reliable operation and precise positioning of the deflection piece, while preventing complete disengagement and maintaining axial stop functionality.
Implementation Method 1
balls, as rolling bodies, roll between said profiles
Implementation Method 2
low friction transfer of balls
Implementation Method 3
in conjunction with lubricant, only an extremely low amount of friction is generated
Data Source
AI summary
A ball screw drive includes two screw drive parts (3, 4), namely a lead screw (3) and a nut (4). The ball screw drive also includes a deflection element (6) for the individual deflection of balls (5) is inserted into a recess (7), formed by one of the screw drive parts (3, 4), such that a gap (16) is formed between the base (15) of the recess (7) and the deflection element (6), and such that lateral contact surfaces (17) of the deflection element (6) which are located next to the recess (7) rest on the screw drive part (3, 4).