Linear Motion Guide Underseal Assembly for Compact Dust Sealing

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Solution Overview

Problem

Existing linear motion guide devices face issues with weak fixing of lip members, complex and costly manufacturing processes, increased seal friction due to multiple lips, and difficulty in applying seals with large dimensions, which affect assembly accuracy and efficiency.

Innovation Solution

A linear motion guide device with an under seal configuration that includes a seal member with a main lip and auxiliary lip, attached to the slider using a seal cover with fitting protrusions and holes, allowing for precise positioning and assembly, and adjustable contact states to improve seal efficiency with a compact width dimension.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a lip member is fixed to a holding member with a screw, then the seal structure is assembled, but the restraining force is weak and positional displacement occurs

Engineering Contradiction:
Improvefixing strengthVSAvoidpositioning accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The seal structure is divided into a seal member and a holding member as separate components. The holding member includes a recess that receives the seal member, and a fastening member secures them together. This segmentation allows the seal member to be pre-assembled with the holding member, ensuring accurate positioning before final installation, thereby resolving the contradiction between fixing strength and positioning accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The seal member is preliminarily positioned within the recess of the holding member before the fastening member is fully secured. This preliminary action ensures that the seal member is correctly positioned and restrained during assembly, preventing positional displacement while maintaining reliable fixing strength when the fastening member is engaged.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If multiple lips are formed on a seal, then foreign matter prevention is improved, but seal friction increases

Engineering Contradiction:
Improveforeign matter preventionVSAvoidseal friction
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The seal member features a lip portion with a specific local structure where the lip extends from the seal member body. This local quality design allows the lip to effectively prevent foreign matter entry while maintaining a streamlined profile that minimizes friction. The lip's geometry is optimized to provide sealing functionality without the need for multiple lips, thus reducing seal friction while preserving foreign matter prevention capability.

Inventive Principle:
Principle #3Local quality

3Reliability

If a seal with large width dimension is used to improve sealing, then seal efficiency is enhanced, but application difficulty increases

Engineering Contradiction:
Improveseal efficiencyVSAvoidapplication difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The seal member is designed with an elongated shape extending in the axial direction of the slider, utilizing the length dimension to provide adequate sealing coverage. This dimensional approach allows the seal to achieve sufficient seal efficiency through its extended length rather than requiring a large width, thereby facilitating easier application and installation while maintaining reliable sealing performance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3722630B1Linear motion guide device
Publication Date: 2022.04.06 NSK LTD
  • EP3722630B1 patent drawingFigure 1
  • EP3722630B1 patent drawingFigure 2
  • EP3722630B1 patent drawingFigure 3

AI summary

A slider (2) of a linear motion guide device comprises: a slider main body (2A); a slider end surface component attached to the movement-direction end part of the slider main body (2A); and an underseal (30) that seals a gap between a guide rail (1) and the slider (2). The underseal (30) has a seal member (31) comprising a main lip (31g) that contacts the guide rail (1). The seal member (31) has a main-body-side lip part (31e) that projects toward a lower surface (6c) of the slider main body (2A) and extends along the movement direction of the slider (2). The main-body-side lip part (31e) contacts both the lower surface (6c) of the slider main body (2A) and a lower surface of the slider end surface component. This makes it possible to maintain high dust prevention and waterproofing properties between the underseal and the lower surfaces of the slider main body and the slider end surface component.