Planetary Coffee Mill Gear Layout for Low-Noise Compact Reduction
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Solution Overview
Problem
Fully automatic coffee machines with integral coffee grinders face issues of excessive noise, complex assembly, and limited axial length due to a high number of parts, which complicates installation and repair.
Innovation Solution
A coffee grinder design featuring a planetary gear with planetary rods having two axially adjacent sections of different diameters, which reduce the axial length and number of parts, and incorporate helical gearing to minimize noise, allowing for high reduction ratios and easier assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional planetary gear with multiple separate components is used, then the reduction ratio can be achieved, but the axial overall length becomes excessively long and the number of parts increases
Solution Approach 1:
The patent combines multiple gear stages into a single integrated planetary gear unit where the sun gear, planetary gears, and ring gear work together in one compact assembly. This merging of components achieves high reduction ratios without requiring multiple separate gear stages stacked axially, thereby reducing the overall axial length while maintaining the required power transmission capability.
Solution Approach 2:
The planetary gear system employs a nested configuration where planetary gears are arranged around the sun gear, and the ring gear encloses the entire planetary assembly. This nesting allows multiple gear engagement points to occupy the same axial space, achieving compound reduction ratios within a compact axial footprint.
2Power
If a conventional planetary gear with multiple separate components is used, then the reduction ratio can be achieved, but the number of parts increases making assembly and repair difficult
Solution Approach 1:
The patent integrates the planetary gear mechanism into a unified assembly where the sun gear, planetary gears mounted on a carrier, and ring gear function as a coordinated unit. This merging reduces the number of separately assembled components compared to multi-stage gear systems, simplifying both assembly and repair processes while achieving the required reduction ratio.
3Power
If a conventional planetary gear design is used, then the reduction ratio can be achieved, but the noise level becomes excessively high
Solution Approach 1:
The planetary gear system distributes the power transmission load across multiple planetary gears that engage with the sun and ring gears in a periodic, alternating manner. This periodic engagement smooths out vibrations and noise compared to single-point gear contacts, as the multiple gear meshing points operate in sequence, reducing overall noise emission while maintaining high reduction ratios.
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 a significant reduction in noise, simplifies assembly and repair, and reduces the axial length while enabling high reduction ratios, making it more efficient and cost-effective.
Implementation Method 1
a reduction gear (4) designed as a planetary gear being arranged between the drive motor (1) and the grinder
Implementation Method 2
the axial sections rotate at the same speed both about the respective planetary rod axis of rotation and about the axis of rotation of the sun wheel
Implementation Method 3
incorporate helical gearing to minimize noise
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a coffee mill, in particular for installation in automatic coffee machines, comprising an electric drive motor (1) for driving a grinder, wherein a reduction gearing (4) designed as a planetary gearing is arranged between the drive motor (1) and the grinder, the sun gear (3) of which reduction gearing can be driven by the drive motor (1). According to the invention, the planetary gearing has a plurality of planet bars (8) arranged around the sun gear (3) in the circumferential direction, which planet bars comprises a first axial section (7), which meshes with the sun gear (3), and an axially adjacent second axial section (9), which has a second diameter that is different from, preferably smaller than, a first diameter of the first axial section (7) and which meshes with a stationary ring gear (11), and the toothed bars are arranged so as to drive an output element (15) by means of the first axial sections (7) of the toothed bars.