Roller Guide Device With Matched Curvature Radii

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Solution Overview

Problem

Conventional roller guide devices with special-shaped rollers experience differential sliding or slipping between central concave and end convex surface portions, leading to early wear due to peripheral speed differences, which affects the rolling guide mechanism's rigidity and longevity.

Innovation Solution

The roller guide device features rollers with arcuate central concave and end convex surface portions, where the radii of contact at the axial midpoint and opposite ends are set to the same radius, allowing for point or line contact, thereby reducing differential sliding and enhancing the rolling elements' contact stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rollers with special shape (central concave surface portion and end convex surface portions) are used to provide high rigidity rolling guide mechanism, then rolling guide rigidity is improved, but differential sliding or slipping occurs between central concave surface portion and end convex surface portions due to peripheral speed difference, causing early wear

Engineering Contradiction:
Improverolling guide rigidityVSAvoidroller wear resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention changes the geometric parameters of the roller surfaces by making the cross-sectional configurations of the central concave surface portion and end convex surface portions arcuate shapes with matched radii of curvature. This parameter adjustment ensures that the peripheral speeds at all contact portions become equal, eliminating differential sliding while maintaining the high rigidity provided by the special roller shape.

Inventive Principle:
Principle #35Parameter changes

2Force

If conventional stopper controlled by air pressure is used to overcome weak spring force, then stopping force is improved, but device size and control complexity increase

Engineering Contradiction:
Improvestopping forceVSAvoidcontrol system complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The invention introduces a wedge-shaped groove as an intermediary mechanical structure that converts the rotational motion of the roller into axial movement of the stopper member. This mechanical intermediary eliminates the need for complex air pressure control systems while providing sufficient stopping force through the wedge mechanism's mechanical advantage.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration minimizes sliding wear and extends the lifespan of the guide surfaces by ensuring uniform peripheral speeds across the contact areas, maintaining the rolling guide mechanism's rigidity and reducing wear.

Implementation Method 1

rollers that are interposed in a freely rollable manner between the arcuate guide surface of the guide shaft, and the arcuate guide surface of the cylindrical body

Methodology Applied
Scientific EffectRolling contact: Roller

Implementation Method 2

a frictional force

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3173640B1A roller guide device
Publication Date: 2019.06.05 THK CO LTD
  • EP3173640B1 patent drawingFigure 1A~1D
  • EP3173640B1 patent drawingFigure 2A~2B
  • EP3173640B1 patent drawingFigure 3A~3B

AI summary

A roller guide device wherein a roller 1 is interposed between a guide surface C1 of a first guide member 210, which takes an arcuate convex shape, and a guide surface C2 of a second guide member 220, which takes an arcuate concave shape and is in opposition to the guide surface C1.The guide surface C1 of the first guide member 210 and the guide surface C2 of the second guide member 220 have the same center of curvature O, and are located on concentric circles. The roller 1 is provided with a central concave surface portion 3 of which a cross sectional configuration cut by a surface passing through a roller central axis N is an arcuate concave shape, and which is in contact with the convex shaped guide surface C1 of the first guide member 210; and end convex surface portions 5, 5 which continue to the axially opposite sides of the central concave surface portion 3, and of which a cross sectional configuration cut by a surface passing through the roller central axis N is an arcuate convex shape, and which is in contact with the concave shaped guide surface C2 of the second guide member 220.