Planetary Gear Bearing Layout for Kitchen Motor Load Protection

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Solution Overview

Problem

Kitchen appliances with universal electric motors face reduced service life due to tilting moments from axial loads, which directly affect the motor and gear storage, particularly when tools are loaded with foodstuffs, leading to potential damage of plastic gear stages.

Innovation Solution

A kitchen appliance with a planetary gear drive system that incorporates a ball bearing to absorb axial and radial forces, distributing them to the transmission housing, thereby protecting the motor and eliminating the need for separate motor bearings, using a ball bearing with an inner and outer ring arrangement and guide grooves for force transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a universal electric motor is used to power the kitchen appliance, then the appliance can achieve high speed and compact design, but the motor bearing is directly exposed to tilting moments from axial loads, reducing service life

Engineering Contradiction:
Improvemotor speedVSAvoidmotor service life
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent introduces a ball bearing as an intermediary component between the motor and the planetary gear. This ball bearing absorbs the tilting moments and axial loads, preventing them from being transmitted directly to the motor bearing. The ball bearing acts as a mediator that protects the motor while allowing the high-speed operation to continue.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If plastic gear stages are used in the planetary gear, then manufacturing cost is reduced, but the gears are vulnerable to damage from tilting moments and axial loads

Engineering Contradiction:
Improvegear manufacturing costVSAvoidgear resistance to tilting moments
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The ball bearing serves as a protective intermediary that shields the plastic gear stages from harmful tilting moments. By absorbing these loads before they reach the plastic gears, the ball bearing enables the use of cost-effective plastic materials while preventing gear damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The ball bearing provides beforehand cushioning by being positioned to receive and absorb tilting moments before they can affect the plastic gear stages. This preventive measure protects the weaker plastic components from overload.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If additional motor bearings are added to protect against tilting moments, then motor service life is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvemotor service lifeVSAvoidbearing arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the function of protecting against tilting moments into the existing ball bearing that is already part of the planetary gear structure. Instead of adding separate motor bearings, the design combines the load-absorbing function with the existing gear support structure, avoiding additional complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The ball bearing in the planetary gear is given a dual function: it supports the planetary gear operation and simultaneously absorbs tilting moments to protect the motor. This multi-functionality eliminates the need for separate protective bearings.

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

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 solution effectively absorbs and distributes tilting moments, enhancing the service life of the electric motor and planetary gear by transferring forces to the gearbox housing, reducing the risk of damage and allowing for cost-effective manufacturing without additional motor support.

Implementation Method 1

the planet carrier being arranged on a roller bearing in the transmission housing. According to the invention, the rolling bearing is a ball bearing

Methodology Applied
Scientific EffectBall bearing: Ball Bearing

Data Source

PatentEP2432357B1Kitchen appliance comprising a planetary gear
Publication Date: 2015.07.22 BSH HAUSGERATE GMBH
  • EP2432357B1 patent drawingFigure 1
  • EP2432357B1 patent drawingFigure 2

AI summary

The present invention relates to a kitchen appliance (1), comprising a drive unit (2), wherein the drive unit (2) comprises a planetary gear (3), which comprises a sun gear (4), at least one planet wheel (5) disposed on a planet carrier (6), and a ring gear (7) disposed in a gear housing (8) of the planetary gear (3), wherein the planet carrier (6) drives an output shaft (17).