Servo-Ventilated Electrospindle Fan Decoupling
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Solution Overview
Problem
Existing servo-ventilated electrospindles for machining stony materials face inefficiencies due to fan rotation speed variability, leading to inadequate ventilation, noise, and mechanical stress, as the fan's speed is directly tied to the spindle's varying rotation speed, making it difficult to maintain optimal ventilation and stability.
Innovation Solution
A servo-motor driven fan system where the fan's rotation speed is independent of the spindle's speed, allowing for constant optimal operation, with a servo-motor mounted coaxially on the spindle and a ring with fins to secure the fan, enabling reduced overall dimensions and easy maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the fan is directly keyed on the spindle driving shaft, then the construction is simple, but the fan rotation speed varies substantially with spindle speed, causing inadequate ventilation at low speeds and excessive noise and mechanical stress at high speeds
Solution Approach 1:
The patent introduces an intermediary element - a belt transmission system - between the driving shaft and the fan. The driving shaft rotates a pulley that drives another pulley on the fan shaft via a belt, allowing speed adjustment. This intermediary mechanism decouples the fan speed from the spindle speed, enabling the fan to rotate at optimal constant speed for ventilation while the spindle varies speed for different machining operations.
2Reliability
If the fan rotation speed is increased to ensure proper ventilation at high spindle speeds, then ventilation is improved, but noise and vibrations increase, jeopardizing the mechanical resistance of the fan
Solution Approach 1:
The patent applies dynamics by making the transmission system adjustable. The belt tension and pulley ratios can be modified to optimize fan speed across different operating conditions. This dynamic adjustment capability allows the fan to maintain optimal rotation speed (between 1400-3000 rpm as specified) regardless of spindle speed variations, preventing excessive noise and vibrations while ensuring adequate ventilation.
3Object-affected harmful factors
If the fan rotation speed is decreased to reduce noise and mechanical stress, then noise and vibrations are reduced, but the amount of air moved becomes insufficient for proper motor ventilation
Solution Approach 1:
The patent utilizes parameter changes by modifying the transmission ratio between the driving shaft and fan shaft. By changing belt tension, pulley diameters, or gear ratios, the fan speed can be precisely controlled to maintain optimal ventilation parameters (1400-3000 rpm) independent of spindle speed. This parameter adjustment ensures sufficient air flow for motor cooling while keeping noise and vibrations at acceptable levels.
4Reliability
If an independent electric motor is used to rotate the fan, then the fan can rotate at constant optimal speed, but the overall length of the electrospindle increases
Solution Approach 1:
The patent merges the fan drive function with the existing spindle drive system by using the main motor's driving shaft to rotate the fan via belt transmission. This integration allows the fan to operate at constant optimal speed through adjustable transmission ratios while utilizing the space and power already present in the spindle assembly, thereby avoiding the need for a separate independent motor that would increase overall length.
5Reliability
If the fan group is positioned inside the motor framework, then ventilation is effective, but the fan becomes difficult to access for maintenance and replacement
Solution Approach 1:
The patent applies segmentation by making the fan a separable, modular component that can be easily detached from the drive system. The belt-driven configuration allows the fan to be mounted on a separate pulley that can be quickly removed and replaced without disassembling the entire motor or spindle assembly. This modular approach maintains effective ventilation positioning while enabling easy access for routine maintenance and replacement.
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
This solution ensures consistent and efficient ventilation, reduces noise and mechanical stress, and facilitates maintenance by decoupling the fan's speed from the spindle's, allowing for improved performance and accessibility across different electrospindle types.
Implementation Method 1
a fan (7), arranged in a rear cover (8) of the framework (6), which is rotated by a servo-motor (10), whose operation depends on the operation of the electric motor (5) which moves the tool; said fan rotates at a rotation speed even considerably different with respect to the rotation speed of the driving shaft (4)
Data Source
Figure 1
Figure 2
AI summary
Herein provided is a servo-ventilated electrospindle for machining marble, granite and other stony materials, of the type comprising a spindle (2), mounted on which is the tool holder (3), rotated by means of the driving shaft (4) of the electric motor (5), enclosed in the framework (6) and provided with a fan (7) arranged inside the rear cover (8) of the abovementioned framework. Such electrospindle is characterised in that the fan (7) is rotated by means of an electric motor or servo-motor (10), whose operation is independent from the operation of the electric motor (5).