Roller Screw Mechanism Axial Broaching Gear Teeth

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Solution Overview

Problem

Current roller screw mechanisms face high manufacturing costs and angular misalignments due to complex gear cutting operations, leading to increased production time and potential deformations.

Innovation Solution

The roller screw mechanism features synchronizing gear teeth with specific convex profiles and root diameters, allowing for single-pass axial broaching to form gear teeth without interference with the thread, reducing manufacturing time and aligning teeth perfectly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If gear teeth are formed on the nut using conventional gear cutting operations, then the synchronizing gear teeth can be formed, but the manufacturing time increases and angular misalignments occur

Engineering Contradiction:

Improveangular alignment of gear teethVSAvoidmanufacturing time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent replaces conventional gear cutting operations with axial broaching operations. The broaching tool forms both synchronizing gear teeth in a single axial pass without requiring the nut to be turned, eliminating the sequential cutting process that caused time delays and angular misalignments.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention segments the gear tooth formation process by positioning the two synchronizing gear teeth at different radial locations relative to the thread. The root diameter of each gear tooth is made less than the inside diameter of the inner thread, allowing independent formation of each gear tooth in a single axial broaching operation.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If multiple gear cutting operations are performed to form gear teeth on the nut, then the gear teeth can be formed, but the manufacturing cost increases

Engineering Contradiction:

Improvemanufacturing costVSAvoidmanufacturing process complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the formation of both synchronizing gear teeth into a single axial broaching operation. Instead of performing separate cutting operations for each gear tooth, the broaching tool forms both teeth simultaneously in one pass, reducing the number of operations and associated costs.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention extracts the gear tooth formation process from the conventional multi-step cutting sequence and implements it as a single axial broaching operation. This extraction simplifies the manufacturing process by removing unnecessary intermediate steps such as turning the nut and performing multiple cutting operations.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If conventional gear cutting operations are used, then gear teeth can be formed, but angular misalignments cause deformations and deterioration

Engineering Contradiction:

Improveservice life of mechanismVSAvoidangular alignment of gear teeth

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10041573B2Roller screw mechanism with integrated ring gears and associated manufacturing method

Publication Date: 2018.08.07 EWELLIX AB

AI summary

A roller screw mechanism comprising a screw having an outer thread, a nut disposed around and coaxially with the screw. The nut includes an inner thread. A plurality of rollers are disposed radially between the screw and the nut and are each provided with an outer thread engaged with the outer and inner threads of the screw and of the nut and with two outer gear teeth. The mechanism additionally comprises two synchronizing gear teeth that are formed on the nut and are each engaged with one of the gear teeth of the rollers. The root diameter of each gear teeth is less than the inside diameter of the inner thread of the nut.