Ball Screw Linear Actuator Guide Projection Detent Stopper

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Solution Overview

Problem

Existing linear actuators with ball screw mechanisms face issues of complex structures due to separate detent and stopper functions, leading to radial load generation, uneven wear, and increased friction, which complicates long-term operation and increases manufacturing costs.

Innovation Solution

The integration of a guide projection and stopper function within the detent mechanism, where the guide projection is designed to engage with a guide groove, allowing for both detent and stopper functions without additional components, preventing radial load and uneven wear by ensuring surface contact and reducing the need for a cam follower.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate detent and stopper functions are provided in the ball screw mechanism, then the detent and stopper functionality is ensured, but the structure becomes complex and radial load is generated

Engineering Contradiction:
Improvedetent and stopper functionalityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the detent function and stopper function into a single integrated guide projection structure. The guide projection simultaneously provides detent engagement with the guide groove and stopper engagement with the abutting surface, eliminating the need for separate components and reducing structural complexity while maintaining both functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The guide projection is designed as a multi-functional component that performs both detent and stopper functions. By making the guide projection universal, the patent reduces the number of parts needed in the ball screw mechanism while ensuring reliable operation for both detent and stopper requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If separate detent and stopper components are used, then the functionality is ensured, but additional components increase manufacturing costs

Engineering Contradiction:
Improvedetent and stopper functionalityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the detent and stopper components into a single guide projection structure, reducing the total number of parts that need to be manufactured, assembled, and quality-checked. This integration directly reduces manufacturing costs while maintaining the required functionality.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If traditional detent mechanism is used without stopper integration, then the detent function works, but radial load is generated causing uneven wear

Engineering Contradiction:
Improvedetent functionVSAvoidradial load and uneven wear
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent combines the detent and stopper functions into a single guide projection that engages with both the guide groove and abutting surface. This integration ensures that axial loads are properly transmitted through the guide projection to the abutting surface, preventing radial load generation and the associated uneven wear on the ball screw mechanism.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2520829B1Linear actuator
Publication Date: 2016.03.02 NSK LTD
  • EP2520829B1 patent drawingFigure 1
  • EP2520829B1 patent drawingFigure 2
  • EP2520829B1 patent drawingFigure 3

AI summary

A linear actuator is provided which is able to simplify its structure by adding a stopper function, too, to a detent mechanism and to prevent generation of radial load.. The linear actuator comprises a ball screw mechanism (20), to which a rotational driving force is transmitted, for converting a rotational motion into a linear motion. The ball screw mechanism (20) comprises radially projecting guide projections (36, 37) provided in a linear motion component (24), and a guide groove (40c) arranged in a securing portion (14b) facing the linear motion component (24) and is engaged with the guide projections (36, 37) to guide the guide projections (36, 37) in an axial direction. The guide projection (36) has a projection (36a) projecting by the predetermined length, while engaging into the guide groove (40c), at a stroke end of the linear motion component (24) and a locking portion (25d) provided in a rotary motion component (22) is locked to the projection (36a) of the guide projection (36).