Linear Motion Guide Resin Return Guide Stepped Groove

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Solution Overview

Problem

Conventional linear motion guide devices face issues with ball collision at the connection portion between the return guide and the slider, leading to hindered smooth circulation and increased manufacturing costs due to required post-processing for flush connections.

Innovation Solution

A linear motion guide device with a guide rail and slider featuring arc-shaped raceway grooves, utilizing a return guide made of resin with a direction changing passage and a stepped portion at the connection point, where the guide face of the return guide is positioned closer to the curvature center than the slider's raceway groove surface, reducing collisions and eliminating the need for post-processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the guide face of the return guide is positioned closer to the curvature center than the raceway groove surface, then ball collisions with the slider are reduced and circulation smoothness is improved, but a stepped portion is formed at the connection point requiring post-processing

Engineering Contradiction:
Improvecirculation smoothnessVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention converts the harmful stepped portion, which was previously a defect requiring post-processing, into a beneficial feature by positioning it to function as a ball retention structure. The stepped portion prevents balls from falling off the end of the raceway groove, transforming a manufacturing inconvenience into a functional advantage that enhances ball circulation reliability

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The return guide is made of resin material instead of metal, making it cheaper and easier to manufacture. The resin material allows for direct formation of the stepped portion during molding without requiring additional post-processing operations, reducing manufacturing complexity while maintaining functional performance

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Ease of manufacture

If a flush connection is made between the return guide and slider raceway groove, then manufacturing steps are reduced, but ball collisions against the slider end face increase causing noise and vibration

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidnoise and vibration
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention introduces the stepped portion as an intermediary structure between the return guide and slider raceway groove. This stepped portion serves as a buffer zone that prevents balls from directly colliding with the slider end face, thereby reducing noise and vibration while maintaining a simple manufacturing process without requiring post-processing operations

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If the return guide is made of resin material, then manufacturing cost and complexity are reduced, but the guide face positioning precision may be affected

Engineering Contradiction:
Improvemanufacturing cost and complexityVSAvoidguide face positioning precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention changes the material parameter of the return guide from metal to resin, which allows for more flexible manufacturing and positioning. The resin material can be molded to achieve the precise positioning of the guide face relative to the raceway groove, and the stepped portion can be directly formed during molding, reducing both manufacturing cost and complexity while maintaining the required positioning precision

Inventive Principle:
Principle #35Parameter changes

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 solution results in a low-noise, high-operability linear motion guide device with reduced manufacturing complexity and cost, as the resin return guide absorbs collisions and prevents ball collisions with the slider's shoulder portion, ensuring smooth circulation and minimizing vibration and noise.

Implementation Method 1

the resin return guide absorbs collisions and prevents ball collisions with the slider's shoulder portion, ensuring smooth circulation and minimizing vibration and noise

Methodology Applied
Scientific EffectCollision absorption: Damping

Data Source

PatentEP3115633B1Linear motion guide device
Publication Date: 2018.05.23 NSK LTD
  • EP3115633B1 patent drawingFigure 1~2
  • EP3115633B1 patent drawingFigure 3~5
  • EP3115633B1 patent drawingFigure 6~8

AI summary

Provided is a linear motion guide device that is less noisy and excellent in operability. A concave groove (36) of a return guide (35) and a raceway groove (11) of a slider (2) are not smoothly continued at a connection portion therebetween, where a stepped portion (44) is formed. At a groove bottom portion (11a) of the raceway groove (11) of the slider (2) and the neighboring portion thereof, the surface of the raceway groove (11) of the slider (2) is located to be closer to a curvature center (O) of the raceway groove (11) of the slider (2) than the surface of the concave groove (36) of the return guide (35) is. At a groove shoulder portion (11b) of the raceway groove (11) of the slider (2) and the neighboring portion thereof, the surface of the concave groove (36) of the return guide (35) is located to be closer to the curvature center (O) of the raceway groove (11) of the slider (2) than the surface of the raceway groove (11) of the slider (2) is.