Power Tool Spindle Support Layout for Lower Gear Housing Height

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Solution Overview

Problem

Existing power tools face challenges in reducing the height of the gear housing while maintaining effective rotation of tool accessories.

Innovation Solution

The power tool design arranges the bearing on the radially outer side of the gear, allowing the spindle to be shortened, and incorporates a gear recess to house additional components, reducing the overall gear housing height.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the bearing is fitted onto the spindle, then the spindle is supported for rotation, but the spindle length increases and the gear housing height increases

Engineering Contradiction:

Improvespindle supportVSAvoidgear housing height

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The bearing is repositioned from a conventional axial arrangement (along the spindle axis) to a radial arrangement (on the radially outer side of the gear). This dimensional change allows the bearing to support the spindle rotation while occupying radial space instead of axial space, thereby reducing the gear housing height in the up-down direction without compromising spindle support functionality

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Length of stationary object

If the gear housing height is reduced, then the power tool becomes more compact, but the space for accommodating components is reduced

Engineering Contradiction:

Improvegear housing heightVSAvoidcomponent accommodation space

Core Design Contradiction:

Length of stationary objectVSVolume of stationary object

Solution Approach 1:

The bearing is nested within the radial space of the gear structure, specifically positioned on the radially outer side of the gear. This nesting arrangement allows the bearing to be accommodated within the existing gear footprint without requiring additional axial space, thereby reducing gear housing height while maintaining adequate space for all components

Inventive Principle:

Principle #7Nested doll (Nesting)

3Length of stationary object

If the bearing is arranged on the radially outer side of the gear, then the gear housing height is reduced, but the bearing arrangement becomes more complex

Engineering Contradiction:

Improvegear housing heightVSAvoidbearing arrangement

Core Design Contradiction:

Length of stationary objectVSDevice complexity

Solution Approach 1:

The bearing arrangement is merged with the existing gear structure, where the bearing is positioned to work in conjunction with the gear's radial geometry. The gear housing is designed to accommodate the bearing in this radial position, integrating the support function into the existing structural framework rather than adding separate complex mounting mechanisms

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12558767B2Power tool

Publication Date: 2026.02.24 MAKITA CORP

AI summary

A power tool has a motor, an output shaft, a spindle, a gear, a gear housing and a bearing. The spindle is configured to be rotated around a drive axis crossing an extending direction of the output shaft. The gear is fitted on the spindle and configured to transmit rotation of the output shaft to the spindle. The gear housing houses the spindle, the gear and the bearing with the lower end part of the spindle protruded downward. The bearing is arranged on the radially outer side of the gear and configured to support the spindle so as to be rotatable around the drive axis.