Work Machine Spindle Seal Structure for Bearing Dust Protection

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Solution Overview

Problem

Powder dust generated during machining work enters the bearing supporting the spindle, hindering its smooth rotation and degrading workability in work machines like electric grinders.

Innovation Solution

A work machine design featuring a gear housing with a spindle, a bearing, a sealing member, and a restricting member that overlaps with the inner race in the radial direction, preventing powder dust entry into the bearing by restricting the sealing member's movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the spindle is positioned close to the machining work area, then workability is improved, but powder dust enters the bearing more easily

Engineering Contradiction:

ImproveworkabilityVSAvoidpowder dust entry into bearing

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A sealing member is introduced as an intermediary component between the spindle and the bearing. This sealing member extends in the radial direction of the spindle and overlaps with the inner race of the bearing, creating a barrier that prevents powder dust from entering the bearing while allowing the spindle to maintain its position close to the machining area for good workability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sealing member is positioned in the radial direction of the spindle, creating a protective barrier in a different dimension from the axial position of the bearing. This radial extension allows the sealing member to effectively block powder dust paths without interfering with the spindle's axial positioning for machining operations

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If the sealing member is made movable, then adaptability is improved, but sealability deteriorates

Engineering Contradiction:

Improvesealing member adjustabilityVSAvoidsealability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The sealing member is pre-positioned and fixed at an optimal location where it overlaps with the inner race of the bearing in the radial direction. This preliminary positioning ensures maximum sealability against powder dust while the restricting member prevents any subsequent movement that would compromise the seal

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A restricting member is introduced as an intermediary component that prevents the sealing member from moving in the axial direction. This restricting member ensures the sealing member remains firmly positioned at the optimal sealing location, maintaining reliable protection against powder dust entry

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12390900B2Work machine

Publication Date: 2025.08.19 KOKI HLDG CO LTD

AI summary

The work machine includes: a gear housing; a spindle protruding in a first direction from the gear housing; a bearing held by the gear housing and including an inner race and an outer race, the bearing rotatably supporting the spindle; a tip tool attachment portion to which a tip tool is attachable, the tip tool attachment portion being provided at the spindle; a sealing member positioned further in the first direction than the bearing; and a restricting member for restricting the sealing member from moving in the first direction. At least a part of the sealing member is overlapped with the inner race in an axial direction of the spindle. The restricting member is held either by the spindle or by the gear housing.