Parallel Roller Paths in Roller Screw Design
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Solution Overview
Problem
Roller screws face interference issues between roller end surfaces and grooves when cross-arranged or when using separate outward- and return-loaded roller groups, leading to reduced load capacity and potential depression in grooves, which can result in shortened contact lengths and reduced load-bearing capabilities.
Innovation Solution
A roller screw design with parallel-arranged rollers in multiple paths, where each path bears loads in opposite directions along the screw shaft axis, with specific angles and thread configurations to prevent interference and balance loads, allowing for adjustable load distribution and increased axial load capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If rollers are cross-arranged in the roller rolling path, then the roller screw can bear loads in both directions along the axis of the screw shaft, but the end surface of the roller interferes with the wall surface of the roller rolling groove, causing depression and shortened contact length
Solution Approach 1:
The roller screw is divided into multiple independent roller rolling paths (first, second, third, and fourth paths). Each path contains rollers arranged in a specific pattern that bears load in one direction. By combining multiple paths, the system achieves bidirectional load capacity without requiring cross-arranged rollers that cause interference.
Solution Approach 2:
Instead of arranging rollers in a two-dimensional cross-pattern within a single plane, the invention distributes rollers across multiple three-dimensional paths with different spatial orientations. This dimensional transition allows rollers to bear loads in opposite directions without their end surfaces interfering with the groove walls.
2Reliability
If the axial length of the roller is shortened to prevent end surface interference, then the interference problem is avoided, but the allowable load of the roller is proportionately reduced
Solution Approach 1:
The load-bearing function is segmented across multiple roller paths rather than relying on a single long roller. Each path contains rollers of optimized length that prevent groove interference while maintaining adequate load capacity. The combined effect of multiple paths achieves the total required load capacity.
Solution Approach 2:
Multiple roller paths are merged to work together in bearing loads. The first and second paths bear loads in one direction, while the third and fourth paths bear loads in the opposite direction. This merging compensates for the reduced individual roller length, maintaining overall system load capacity.
3Force
If separate outward-loaded and return-loaded roller groups are arranged along the axis of the screw shaft, then loads in both directions can be borne, but the same interference problem occurs since both groups roll on one roller rolling groove
Solution Approach 1:
The roller groups are segmented into different spatial paths rather than sharing a single groove. Outward-loaded rollers are assigned to the first and second paths, while return-loaded rollers are assigned to the third and fourth paths. This segmentation eliminates the interference problem that occurs when both groups share the same groove.
Solution Approach 2:
The invention transitions from a one-dimensional arrangement where both roller groups share a single groove to a multi-dimensional configuration with separate paths. This spatial separation in multiple dimensions allows both outward-loaded and return-loaded roller groups to operate without interference.
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 design prevents end surface interference, maintains balanced loads, and allows for optional adjustment of load capacity, even with limited roller diameters, simplifying machining and evaluation processes.
Implementation Method 1
a roller screw having a screw shaft, a nut and rollers rotatably disposed therebetween... the screw shaft has, instead of the ball rolling groove, a roller rolling groove formed thereon for rolling the rollers
Data Source
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AI summary
The present invention provides a roller screw which bears loads in both directions along the axis of the screw shaft and which is also capable of preventing interference between each roller end surface and roller rolling grooves. Between roller rolling surfaces 1a, 1b of the screw shaft 1 and roller rolling surfaces 2a, 2b, respectively, of the nut 2, there are formed two or more roller rolling paths 3a, 3b, respectively. In one roller rolling path 3a, plural rollers 4a are parallel-arranged, and also in another roller rolling path 3b, plural rollers 4b are parallel-arranged. The rollers 4a arranged in the one roller rolling path 3a bear a load in one direction (1) along the axis of the screw shaft 1, while the rollers 4b arranged in the other roller rolling path 3b bear a load in the opposite direction (2) along the axis of the screw shaft 1.