Hollow Spindle Drive Layout for Quieter Automatic Coffee Machines
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Solution Overview
Problem
Fully automatic coffee machines for domestic use face challenges with expensive, noisy steel spindles due to custom-made dimensions and high thread pitches, while plastic spindles are less resilient and require larger diameters, increasing space requirements and noise emissions.
Innovation Solution
A hollow spindle design with the motor and gear completely enclosed within the spindle cavity, utilizing internal teeth for mechanical connection and potentially acting as an external rotor motor, reduces space and noise while protecting components from contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a solid steel spindle is used in fully automatic coffee machines for domestic use, then the spindle provides high strength and stability, but the machine occupies more space and the production cost increases due to custom-made dimensions
Solution Approach 1:
The drive unit components (motor and gear) are nested inside the hollow cavity of the spindle, allowing the spindle to be made lighter and smaller while maintaining structural integrity. The motor is positioned within the internal cavity, and the gear is arranged inside the spindle structure, effectively utilizing the internal space to reduce overall volume.
Solution Approach 2:
The spindle is segmented into a hollow structure with an internal cavity that houses the drive unit components. This segmentation allows the spindle to maintain external strength while reducing material usage and overall volume. The hollow construction separates the structural function from the space-occupying solid material.
2Manufacturing precision
If a steel spindle with small thread pitch is used, then the spindle provides precise movement control, but the operating noise increases due to high number of revolutions required
Solution Approach 1:
The patent replaces the traditional steel spindle with a plastic spindle that uses a different thread pitch optimization approach. The plastic material allows for larger thread pitches while maintaining sufficient precision, thereby reducing the number of revolutions needed and lowering operating noise. The gear mechanism inside the spindle also contributes to noise reduction through enclosed mechanical transmission.
3Ease of manufacture
If a plastic spindle is used in fully automatic coffee machines for the catering sector, then the spindle can be made with larger diameter and hollow construction for manufacturing efficiency, but the machine housing dimensions must be significantly larger to accommodate it
Solution Approach 1:
The hollow plastic spindle is nested with the drive unit components (motor and gear) inside its cavity. This nesting allows the spindle to maintain a compact external diameter suitable for domestic coffee machines while providing sufficient structural strength. The internal components are arranged to fit within the hollow space, maximizing space utilization.
Solution Approach 2:
The spindle and drive unit are merged into a single integrated structure where the motor and gear are combined within the spindle housing. This merging eliminates the need for separate mounting spaces for the drive components, allowing the entire assembly to fit within the compact dimensions required for domestic coffee machines.
4Device complexity
If the drive unit components are arranged outside the spindle, then the spindle structure is simpler, but the components are exposed to contamination and generate more noise
Solution Approach 1:
The motor and gear are nested inside the hollow cavity of the spindle, providing natural protection against contamination from water, steam, and coffee powder. The spindle wall acts as a barrier, isolating the sensitive drive components from the harsh operating environment while maintaining structural simplicity.
Solution Approach 2:
The hollow cavity that initially seemed to increase complexity is converted into a protective enclosure. The same internal space that could have been considered an added complication becomes a beneficial shield against contamination, while also serving as a noise-reducing enclosure for the moving parts.
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 compact, cost-effective, and noise-reduced spindle that is more resilient and adaptable, enhancing the robustness and operational quietness of the coffee machine.
Implementation Method 1
The drive unit comprises at least one electric motor and possibly also a gear that connects the shaft of the electric motor and the spindle
Implementation Method 2
a gear that connects the shaft of the electric motor and the spindle
Data Source
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AI summary
The invention relates to a fully automatic coffee machine, in particular for household use, having a brewing unit comprising a spindle (10; 18; 19) and a drive unit (20) causing the spindle (10; 18; 19) to rotate during operation, developed in that the spindle (10; 18; 19) is at least partially hollow and at least one part (22; 24; 30) of the drive unit (20) is disposed inside the spindle (10; 18; 19).