Ball Screw Contact Seal Structure for Compact Low-Resistance Sealing

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Solution Overview

Problem

Existing ball screws with multiple seals increase axial length, component costs, and sliding resistance, making them difficult to achieve a small size and effective sealing.

Innovation Solution

A ball screw design featuring a screw shaft with a spiral outer groove, a nut with a spiral inner groove, balls in a rolling path, a circulation member, and a deformable contact seal with a protrusion fitted into a grinding clearance groove, ensuring sealing performance with reduced size and costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two seals are provided in the ball screw to prevent entry of foreign matters and leakage of lubricant, then sealing performance is improved, but axial length of the nut increases and component costs increase

Engineering Contradiction:
Improvesealing performanceVSAvoidaxial length of the nut
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The invention merges the sealing function and the grinding clearance groove function into a single integrated contact seal structure. The contact seal includes a protrusion that fits into the grinding clearance groove, combining the sealing barrier and the heat dissipation clearance into one component, thereby eliminating the need for a separate second seal while maintaining both sealing performance and thermal management.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The contact seal is designed to perform multiple functions simultaneously: it provides sealing against foreign matters and lubricant leakage, while its protrusion fits into the grinding clearance groove to facilitate heat dissipation during grinding operations. This multi-functional design reduces the number of components needed while achieving multiple technical objectives.

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

2Reliability

If two seals are provided in the ball screw to ensure sealing performance, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvesealing performanceVSAvoidnumber of seals
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the sealing function and the grinding clearance groove function into a single integrated contact seal structure. The contact seal includes a protrusion that fits into the grinding clearance groove, combining the sealing barrier and the heat dissipation clearance into one component, thereby eliminating the need for a separate second seal while maintaining both sealing performance and thermal management.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The contact seal is designed to perform multiple functions simultaneously: it provides sealing against foreign matters and lubricant leakage, while its protrusion fits into the grinding clearance groove to facilitate heat dissipation during grinding operations. This multi-functional design reduces the number of components needed while achieving multiple technical objectives.

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

3Reliability

If two seals are provided in the ball screw to prevent leakage, then sealing performance is improved, but sliding resistance increases

Engineering Contradiction:
Improvesealing performanceVSAvoidsliding resistance
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The invention merges the sealing function and the grinding clearance groove function into a single integrated contact seal structure. The contact seal includes a protrusion that fits into the grinding clearance groove, combining the sealing barrier and the heat dissipation clearance into one component, thereby eliminating the need for a separate second seal while maintaining both sealing performance and thermal management.

Inventive Principle:
Principle #5Merging (Combining)

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 design achieves sealing performance with a small size and limited component costs while reducing sliding resistance.

Implementation Method 1

the contact seal is an elastically deformable annular plate material

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4607063A1Ball screw
Publication Date: 2025.08.27 NSK LTD
  • EP4607063A1 patent drawingFigure 1
  • EP4607063A1 patent drawingFigure 2
  • EP4607063A1 patent drawingFigure 3

AI summary

This ball screw comprises: a screw shaft having a spiral outer circumferential screw groove formed on the outer circumferential surface; a nut that is disposed in the surrounding of the screw shaft and that has a spiral inner circumferential screw groove which is formed in the inner circumferential surface and which face the outer circumferential screw groove; a plurality of balls housed in a ball rolling passage formed by the outer circumferential screw groove and the inner circumferential screw groove facing each other; a circulation member for circulating the balls along the ball rolling passage; and a contact seal disposed between the end of the nut and the screw shaft. The outer circumferential screw groove has a grinding relief groove. The contact seal is an elastically deformable ring-shaped plate material in which the inner circumferential edge thereof makes contact with the outer circumferential surface of the screw shaft and which has a protrusion fitted with the grinding relief groove.